Video or image compilation based on zoom list

Abstract

According to the disclosure of this document, zoom list data and zoom list associated information can be signaled hierarchically, so it can reduce the amount of data to be signaled for video / image coding and increase coding efficiency.

Description

Technical Field

[0001] The present disclosure relates to image or video coding, for example, to a coding technique based on a scaling list. Background Art

[0002] Recently, there has been an increasing demand for high-resolution and high-quality images and videos such as ultra-high-definition (HUD) images and 4K or 8K or larger videos in various fields. As image and video data becomes higher in resolution and higher in quality, the amount of information or the number of bits transmitted increases compared to existing image and video data. Therefore, if a medium such as an existing wired or wireless broadband line is used to transmit image data or an existing storage medium is used to store image and video data, the transmission cost and storage cost increase.

[0003] In addition, there has been a recent increase in interest and demand for immersive media such as virtual reality (VR), artificial reality (AR) content, or holograms, and the broadcasting of images and videos having image characteristics different from those of real images, such as game images, has increased.

[0004] Therefore, in order to efficiently compress and transmit or store and play back information of high-resolution and high-quality images and videos having such various characteristics, efficient image and video compression technology is required.

[0005] Furthermore, there are discussions on adaptive frequency weighted quantization techniques in the scaling process in order to improve compression efficiency and increase subjective / objective visual quality. In order to effectively apply this technology, a method for signaling relevant information is required. Summary of the Invention

[0006] Technical issues

[0007] A technical aspect of the present disclosure is to provide a method and apparatus for increasing image coding efficiency.

[0008] Another technical aspect of the present disclosure is to provide a method and apparatus for increasing coding efficiency during scaling.

[0009] Yet another technical aspect of the present disclosure is to provide a method and apparatus for efficiently constructing a zoom list used in a zooming process.

[0010] Yet another technical aspect of the present disclosure is to provide a method and apparatus for hierarchically signaling zoom list related information used in a zooming process.

[0011] Yet another technical aspect of the present disclosure is to provide a method and apparatus for efficiently applying a zoom list-based zooming process.

[0012] Technical Solution

[0013] According to an embodiment of this document, scaling list data may be signaled through an adaptive parameter set (APS), and APS identification information (APS ID) indicating the ID of the APS referenced for scaling list data may be signaled through header information (picture header / slice header / tile group header, etc.).

[0014] According to an embodiment of this document, type information of an APS parameter may be signaled through an APS, and whether a corresponding APS is a zoom list data (zoom list parameter) APS may be indicated based on the type information of the APS parameter.

[0015] According to an embodiment of this document, APS ID number information indicating the number of IDs of APSs related to zoom list data may be signaled through header information, and identification information syntax elements of as many APSs related to zoom list data as the number of APS IDs may be signaled.

[0016] According to an embodiment of this document, available flag information indicating whether scaling list data is available can be signaled hierarchically, and based on the available flag information signaled in a higher level syntax (e.g., SPS), available flag information in a lower level syntax (e.g., picture header / slice header / type group header, etc.) can be signaled.

[0017] According to an embodiment of this document, constraint flag information may be signaled through a general constraint information syntax, and whether available flag information of scaling list data is used may be indicated based on the constraint flag information.

[0018] According to an embodiment of this document, a video / image decoding method performed by a decoding device is provided. The video / image decoding method may include the method disclosed in the embodiment of this document.

[0019] According to an embodiment of this document, a decoding device for performing video / image decoding is provided. The decoding device can execute the method disclosed in the embodiment of this document.

[0020] According to an embodiment of this document, a video / image encoding method performed by an encoding device is provided. The video / image encoding method may include the method disclosed in the embodiment of this document.

[0021] According to an embodiment of this document, a coding apparatus for performing video / image coding is provided. The coding apparatus can execute the method disclosed in the embodiment of this document.

[0022] According to an embodiment of this document, there is provided a computer-readable digital storage medium storing encoded video / image information generated according to the video / image encoding method disclosed in at least one embodiment of this document.

[0023] According to an embodiment of this document, there is provided a computer-readable digital storage medium storing encoding information or encoded video / image information that enables a decoding device to perform the video / image decoding method disclosed in at least one embodiment of this document.

[0024] Beneficial effects

[0025] This document may have various effects. For example, according to an embodiment of this document, the overall image / video compression efficiency can be increased. In addition, according to an embodiment of this document, by applying an effective scaling process, the coding efficiency can be increased and the subjective / objective visual quality can be improved. In addition, according to an embodiment of this document, the scaling list used in the scaling process can be effectively configured, and through this, the scaling list related information can be signaled in a hierarchical manner. In addition, according to an embodiment of this document, the coding efficiency can be increased by effectively applying a scaling process based on a scaling list.

[0026] The effects that can be achieved through the specific embodiments of this document are not limited to the effects listed above. For example, there may be various technical effects that can be understood or derived from this document by a person skilled in the relevant art. Therefore, the specific effects of this document are not limited to those explicitly described in this document, and may include various effects that can be understood or derived from the technical features of this document. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 An example of a video / image coding system to which embodiments of the present disclosure can be applied is schematically shown.

[0028] Figure 2 is a diagram schematically illustrating a configuration of a video / image encoding device to which an embodiment of the present disclosure can be applied.

[0029] Figure 3 is a diagram schematically illustrating a configuration of a video / image decoding device to which an embodiment of the present disclosure can be applied.

[0030] Figure 4 An example of an illustrative intra-prediction-based video / image encoding method to which the embodiments of the present disclosure may be applied is shown.

[0031] Figure 5 An example of an illustrative intra-prediction-based video / image decoding method to which the embodiments of the present disclosure may be applied is shown.

[0032] Figure 6 The intra prediction process is exemplarily shown.

[0033] Figure 7 The inter-frame prediction process is exemplarily shown.

[0034] Figure 8 The hierarchical structure of images / videos used for coding is exemplified.

[0035] Figure 9 and Figure 10 Schematically represents an example of a video / image encoding method and related components according to an embodiment of this document.

[0036] Figure 11 and Figure 12 Schematically represents an example of a video / image decoding method and related components according to an embodiment of this document.

[0037] Figure 13 The structure of a content streaming transmission system to which the present disclosure is applied is schematically shown. DETAILED DESCRIPTION

[0038] This document can be modified in various ways and can have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit this document to specific embodiments. The terms generally used in this specification are used to describe specific embodiments and are not used to limit the technical spirit of this document. Unless otherwise clearly indicated in the context, singular expressions include plural expressions. Terms such as "including" or "having" in this specification should be understood to indicate the presence of characteristics, numbers, steps, operations, elements, components, or combinations thereof described in this specification, without excluding the possibility of the presence or addition of one or more characteristics, numbers, steps, operations, elements, components, or combinations thereof.

[0039] At the same time, in order to facilitate the description of different feature functions, the elements in the drawings described in this document are illustrated independently. This does not mean that each element is implemented as separate hardware or separate software. For example, at least two elements can be combined to form a single element, or a single element can be divided into multiple elements. Implementations in which elements are combined and / or separated are also included in the scope of the rights of this document unless it deviates from the essence of this document.

[0040] This document relates to video / image coding. For example, the methods / embodiments disclosed in this document can be applied to methods disclosed in Versatile Video Coding (VVC). In addition, the methods / embodiments disclosed in this document can be applied to methods disclosed in the Essential Video Coding (EVC) standard, the AOMedia Video 1 (AV1) standard, the second-generation Audio Video Coding standard (AVS2), or next-generation video / image coding standards (e.g., H.267 or H.268).

[0041] This document presents various embodiments of video / image coding, and unless mentioned to the contrary, these embodiments may be performed in combination with each other.

[0042] In this document, video may mean a collection of a series of images according to the passage of time. A picture generally means a unit that represents an image of a specific time period, and a slice / tile is a unit that constitutes a part of a picture in coding. A slice / tile may include one or more coding tree units (CTUs). A tile is a rectangular area of a CTU within a specific tile column and a specific tile row in a picture. A tile column is a rectangular area where the height of the CTU is equal to the height of the picture and the width is specified by a syntax element in the picture parameter set. A tile row is a rectangular area where the height of the CTU is specified by a syntax element in the picture parameter set and the width is equal to the width of the picture. Tile scanning is a specific order sorting of CTUs of a partitioned picture as follows: CTUs can be sorted continuously in a tile by a CTU raster scan, while tiles in a picture can be sorted continuously by a raster scan of tiles of a picture. A slice includes an integer number of complete tiles or an integer number of continuous complete CTU rows within a tile of a picture that can be exclusively contained in a single NAL unit.

[0043] At the same time, a picture can be divided into two or more sub-pictures. A sub-picture can be a rectangular area of one or more slices within the picture.

[0044] A pixel or picture element (pel) may refer to the smallest unit constituting a picture (or image). In addition, "sample" may be used as a term corresponding to a pixel. A sample may generally represent a pixel or a pixel value, and may represent only a pixel / pixel value of a luminance component, or only a pixel / pixel value of a chrominance component.

[0045] A unit may represent a basic unit of image processing. A unit may include at least one of a specific region of a picture and information related to the region. A unit may include a luminance block and two chrominance (e.g., CB, CR) blocks. Depending on the situation, terms such as unit and block, region, etc. may be used interchangeably. In general, an M×N block may include a set (or array) of samples (or sample arrays) or transform coefficients consisting of M columns and N rows.

[0046] In addition, in this document, at least one of quantization / dequantization and / or transform / inverse transform may be omitted. When quantization / dequantization is omitted, the quantized transform coefficient may be referred to as a transform coefficient. When transform / inverse transform is omitted, the transform coefficient may be referred to as a coefficient or a residual coefficient, or, for uniformity of expression, may still be referred to as a transform coefficient.

[0047] In this document, quantized transform coefficients and transform coefficients may be referred to as transform coefficients and scaled transform coefficients, respectively. In this case, residual information may include information about the transform coefficients, and the information about the transform coefficients may be signaled via residual coding syntax. The transform coefficients may be derived based on the residual information (or information about the transform coefficients), and the scaled transform coefficients may be derived by inversely transforming (scaling) the transform coefficients. Residual samples may be derived based on the inverse transform of the scaled transform coefficients. This may also be applied / expressed in other parts of this document.

[0048] In this document, the term "A or B" may mean "only A," "only B," or "both A and B." In other words, in this document, the term "A or B" may be interpreted to mean "A and / or B." For example, in this document, the term "A, B, or C" may mean "only A," "only B," "only C," or "any combination of A, B, and C."

[0049] As used in this document, a slash " / " or a comma may mean "and / or." For example, "A / B" may mean "A and / or B." Thus, "A / B" may mean "only A," "only B," or "both A and B." For example, "A, B, C" may mean "A, B, or C."

[0050] In this document, “at least one of A and B” may mean “only A”, “only B”, or “both A and B”. In addition, in this document, the expression “at least one of A or B” or “at least one of A and / or B” may be interpreted as “at least one of A and B”.

[0051] In addition, in this document, "at least one of A, B, and C" may mean "only A", "only B", "only C", or "any combination of A, B, and C". In addition, "at least one of A, B, or C" or "at least one of A, B, and / or C" may mean "at least one of A, B, and C".

[0052] Furthermore, brackets used in this document may mean "for example." Specifically, when "prediction (intra-frame prediction)" is expressed, it may indicate that "intra-frame prediction" is presented as an example of "prediction." In other words, the term "prediction" in this document is not limited to "intra-frame prediction" and may indicate that "intra-frame prediction" is presented as an example of "prediction." Furthermore, even when "prediction (i.e., intra-frame prediction)" is expressed, it may indicate that "intra-frame prediction" is presented as an example of "prediction."

[0053] In this document, technical features explained separately in one drawing may be implemented separately or may be implemented simultaneously.

[0054] Hereinafter, the preferred embodiment of this document will be described in more detail with reference to the accompanying drawings. Hereinafter, in the accompanying drawings, the same reference numerals are used in the same elements, and repeated description of the same elements may be omitted.

[0055] Figure 1 An example of a video / image coding system to which embodiments of this document can be applied is schematically illustrated.

[0056] refer to Figure 1 The video / image coding system may include a first device (source device) and a second device (receiving device). The source device may transmit the encoded video / image information or data to the receiving device in the form of a file or stream transmission via a digital storage medium or a network.

[0057] The source device may include a video source, an encoding device, and a transmitter. The receiving device may include a receiver, a decoding device, and a renderer. The encoding device may be referred to as a video / image encoding device, and the decoding device may be referred to as a video / image decoding device. The transmitter may be included in the encoding device. The receiver may be included in the decoding device. The renderer may include a display, and the display may be configured as a separate device or an external component.

[0058] The video source can obtain the video / image by capturing, synthesizing or generating the video / image process. The video source may include a video / image capturing device and / or a video / image generating device. The video / image capturing device may include, for example, one or more cameras, a video / image archive including previously captured videos / images, etc. The video / image generating device may include, for example, a computer, a tablet computer and a smart phone, and may (electronically) generate the video / image. For example, a virtual video / image may be generated by a computer or the like. In this case, the video / image capturing process may be replaced by a process that generates relevant data.

[0059] The encoding device can encode the input video / image. The encoding device can perform a series of processes such as prediction, transformation, and quantization for compression and coding efficiency. The encoded data (encoded video / image information) can be output in the form of a bitstream.

[0060] The transmitter can transmit the encoded video / image information or data, output as a bitstream, to a receiver in a receiving device via a digital storage medium or network in the form of a file or streaming. Digital storage media can include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, SSD, etc. The transmitter can include components for generating a media file in a predetermined file format and can also include components for transmitting via a broadcast / communication network. The receiver can receive / extract the bitstream and transmit the received / extracted bitstream to a decoding device.

[0061] The decoding device can decode the video / image by performing a series of processes such as dequantization, inverse transformation, prediction, etc. corresponding to the operation of the encoding device.

[0062] The renderer can render the decoded video / image, and the rendered video / image can be displayed on a display.

[0063] Figure 2 is a diagram schematically illustrating a configuration of a video / image encoding device to which this document can be applied. Hereinafter, the encoding device may include an image encoding device and / or a video encoding device.

[0064] refer to Figure 2 , the encoding device 200 may include an image segmenter 210, a predictor 220, a residual processor 230, an entropy encoder 240, an adder 250, a filter 260, and a memory 270. The predictor 220 may include an inter-frame predictor 221 and an intra-frame predictor 222. The residual processor 230 may include a transformer 232, a quantizer 233, a dequantizer 234, and an inverse transformer 235. The residual processor 230 may also include a subtractor 231. The adder 250 may be referred to as a reconstructor or a reconstructed block generator. According to an embodiment, the image segmenter 210, the predictor 220, the residual processor 230, the entropy encoder 240, the adder 250, and the filter 260 described above may be composed of one or more hardware components (e.g., an encoder chipset or processor). In addition, the memory 270 may include a decoded picture buffer (DPB) and may be composed of a digital storage medium. The hardware components may also include the memory 270 as an internal / external component.

[0065] The image splitter 210 splits the input image (or picture, or frame) input to the encoding device 200 into one or more processing units. As an example, a processing unit may be referred to as a coding unit (CU). In this case, starting from a coding tree unit (CTU) or a largest coding unit (LCU), the coding units may be recursively split according to a quadtree, binary tree, ternary tree (QTBTTT) structure. For example, a coding unit may be divided into multiple coding units of increasing depth based on a quadtree structure, a binary tree structure, and / or a ternary tree structure. In this case, for example, the quadtree structure may be applied first, followed by the binary tree structure and / or the ternary tree structure. Alternatively, the binary tree structure may be applied first. The coding process according to this document may be performed based on the final coding unit that has not been further split. In this case, based on coding efficiency according to image characteristics, the largest coding unit may be directly used as the final coding unit. Alternatively, the coding unit may be recursively split into coding units of increasing depth as needed, so that the optimally sized coding unit can be used as the final coding unit. Here, the coding process may include processes such as prediction, transformation, and reconstruction, which will be described later. As another example, the processing unit may also include a prediction unit (PU) or a transform unit (TU). In this case, the prediction unit and the transform unit may be divided or partitioned from the final coding unit described above. The prediction unit may be a unit for sample prediction, and the transform unit may be a unit for deriving a transform coefficient and / or a unit for deriving a residual signal based on the transform coefficient.

[0066] Depending on the situation, terms such as unit and block, region, etc. may be used interchangeably. In general, an M×N block may represent a set of samples or transform coefficients consisting of M columns and N rows. A sample may generally represent a pixel or a pixel value, and may represent only a pixel / pixel value of a luminance component or only a pixel / pixel value of a chrominance component. A sample may be used as a term corresponding to a pixel or a picture element (pel) of a picture (or image).

[0067] In the encoding device 200, the prediction signal (prediction block, prediction sample array) output from the inter predictor 221 or the intra predictor 222 is subtracted from the input image signal (original block, original sample array) to generate a residual signal (residual block, residual sample array), and the generated residual signal is sent to the transformer 232. In this case, as shown, the unit in the encoder 200 that subtracts the prediction signal (prediction block, prediction sample array) from the input image signal (original block, original sample array) can be referred to as a subtractor 231. The predictor can perform prediction on a processing target block (hereinafter referred to as a "current block") and can generate a prediction block including prediction samples for the current block. The predictor can determine whether to apply intra prediction or inter prediction based on the current block or CU. As discussed later in the description of each prediction mode, the predictor can generate various information related to prediction, such as prediction mode information, and send the generated information to the entropy encoder 240. The information about the prediction can be encoded in the entropy encoder 240 and output in the form of a bitstream.

[0068] The intra-frame predictor 222 can predict the current block by referring to samples in the current picture. Depending on the prediction mode, the reference sample can be located near the current block or separated from the current block. In intra-frame prediction, the prediction mode can include multiple non-directional modes and multiple directional modes. The non-directional mode can include, for example, a DC mode and a planar mode. Depending on the level of detail of the prediction direction, the directional mode can include, for example, 33 directional prediction modes or 65 directional prediction modes. However, this is merely an example, and more or fewer directional prediction modes can be used depending on the settings. The intra-frame predictor 222 can determine the prediction mode applied to the current block by using the prediction mode applied to the neighboring block.

[0069] The inter-frame predictor 221 can derive a prediction block for the current block based on a reference block (reference sample array) specified by a motion vector in a reference picture. To reduce the amount of motion information transmitted in inter-frame prediction mode, motion information can be predicted on a block, sub-block, or sample basis based on the correlation of motion information between neighboring blocks and the current block. Motion information can include a motion vector and a reference picture index. It can also include information about the inter-frame prediction direction (L0 prediction, L1 prediction, Bi prediction, etc.). In the case of inter-frame prediction, neighboring blocks can include spatially neighboring blocks in the current picture and temporally neighboring blocks in a reference picture. The reference picture including the reference block and the reference picture including the temporally neighboring block can be the same or different. Temporally neighboring blocks can be referred to as collocated reference blocks, collocated CUs (colCUs), etc., and the reference picture including temporally neighboring blocks can be referred to as collocated pictures (colPics). For example, the inter-frame predictor 221 can configure a motion information candidate list based on the neighboring blocks and generate information indicating which candidate is used to derive the motion vector and / or reference picture index for the current block. Inter-frame prediction can be performed based on various prediction modes. For example, in the case of skip mode and merge mode, the inter-frame predictor 221 can use the motion information of the neighboring block as the motion information of the current block. In skip mode, unlike merge mode, the residual signal cannot be sent. In the case of motion information prediction (motion vector prediction, MVP) mode, the motion vector of the neighboring block can be used as a motion vector predictor, and the motion vector of the current block can be indicated by signaling the motion vector difference.

[0070] The predictor 220 can generate a prediction signal based on various prediction methods. For example, the predictor can apply intra prediction or inter prediction to predict a block, and can also apply intra prediction and inter prediction simultaneously. This can be referred to as combined inter and intra prediction (CIIP). In addition, the predictor can perform prediction on the block based on an intra block copy (IBC) prediction mode or a palette mode. The IBC prediction mode or palette mode can be used for content image / video coding such as games such as screen content coding (SCC). Although IBC basically performs prediction in the current picture, its execution is similar to inter prediction in that it derives a reference block in the current picture. That is, IBC can use at least one of the inter prediction techniques described in this document. The palette mode can be considered an example of intra coding or intra prediction. When the palette mode is applied, the sample values in the picture can be signaled based on information about the palette index and the palette table.

[0071] The prediction signal generated by the predictor (including the inter-frame predictor 221 and / or the intra-frame predictor 222) can be used to generate a reconstruction signal or to generate a residual signal. The transformer 232 can generate a transform coefficient by applying a transform technique to the residual signal. For example, the transform technique may include at least one of a discrete cosine transform (DCT), a discrete sine transform (DST), a Karhunen-Loève transform (KLT), a graph-based transform (GBT), or a conditional nonlinear transform (CNT). Here, GBT means a transform obtained from a curve graph when the relationship information between pixels is represented by a curve graph. CNT refers to a transform obtained based on a prediction signal generated using all previously reconstructed pixels. In addition, the transform process can be applied to square pixel blocks of the same size, or can be applied to blocks of variable size rather than square blocks.

[0072] The quantizer 233 can quantize the transform coefficients and send them to the entropy encoder 240. The entropy encoder 240 can encode the quantized signal (information about the quantized transform coefficients) and output the encoded signal in a bitstream. The information about the quantized transform coefficients can be referred to as residual information. The quantizer 233 can rearrange the quantized transform coefficients of the block type into a one-dimensional vector form based on the coefficient scanning order, and generate information about the quantized transform coefficients based on the quantized transform coefficients in the one-dimensional vector form. The entropy encoder 240 can perform various encoding methods such as exponential Golomb, context-adaptive variable length coding (CAVLC), context-adaptive binary arithmetic coding (CABAC), etc. The entropy encoder 240 can encode information required for video / image reconstruction in addition to the quantized transform coefficients (e.g., syntax element values, etc.) together or separately. The encoded information (e.g., encoded video / image information) can be transmitted or stored in the form of a bitstream on a unit basis of the network abstraction layer (NAL). The video / image information may also include information about various parameter sets such as an adaptation parameter set (APS), a picture parameter set (PPS), a sequence parameter set (SPS), a video parameter set (VPS), and the like. Furthermore, the video / image information may also include general constraint information. In this document, information and / or syntax elements transmitted from the encoding device to the decoding device using a signal may be included in the video / image information. The video / image information may be encoded using the above-described encoding process and included in the bitstream. The bitstream may be transmitted over a network or stored in a digital storage medium. Here, the network may include a broadcast network, a communication network, and / or the like, and the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, SSD, and the like. A transmitter (not shown) that transmits the signal output from the entropy encoder 240 or a memory (not shown) that stores the signal may be configured as an internal / external component of the encoding device 200, or the transmitter may be included in the entropy encoder 240.

[0073] The quantized transform coefficients output from the quantizer 233 can be used to generate a prediction signal. For example, by applying dequantization and inverse transformation to the quantized transform coefficients via the dequantizer 234 and the inverse transformer 235, a residual signal (residual block or residual sample) can be reconstructed. The adder 155 adds the reconstructed residual signal to the prediction signal output from the inter-frame predictor 221 or the intra-frame predictor 222, so that a reconstructed signal (reconstructed picture, reconstructed block, reconstructed sample array) can be generated. When there is no residual for the processing target block, as in the case of applying skip mode, the prediction block can be used as a reconstructed block. The adder 250 can be referred to as a reconstructor or a reconstructed block generator. The generated reconstructed signal can be used for intra-frame prediction of the next processing target block in the current picture, and as described later, can be used for inter-frame prediction of the next picture performed by filtering.

[0074] Furthermore, during the picture encoding and / or reconstruction process, luma mapping and chroma scaling (LMCS) may be applied.

[0075] The filter 260 can improve the subjective / objective video quality by applying filtering to the reconstructed signal. For example, the filter 260 can generate a modified reconstructed picture by applying various filtering methods to the reconstructed picture, and the modified reconstructed picture can be stored in the memory 270, especially in the DPB of the memory 270. Various filtering methods may include, for example, deblocking filtering, sample adaptive offset, adaptive ring filtering, bilateral filtering, etc. As discussed later in the description of each filtering method, the filter 260 can generate various information related to filtering and send the generated information to the entropy encoder 240. The information about filtering can be encoded in the entropy encoder 240 and output in the form of a bitstream.

[0076] The modified reconstructed picture sent to the memory 270 can be used as a reference picture in the inter-frame predictor 221. Accordingly, the encoding apparatus can avoid prediction mismatch in the encoding apparatus 100 and the decoding apparatus when applying inter-frame prediction, and can also improve encoding efficiency.

[0077] The memory 270DPB can store the modified reconstructed picture so that it can be used as a reference picture in the inter-frame predictor 221. The memory 270 can store the motion information of the blocks in the current picture from which the motion information has been derived (or encoded) and / or the motion information of the blocks in the reconstructed picture. The stored motion information can be sent to the inter-frame predictor 221 to be used as the motion information of the neighboring blocks or the motion information of the temporally neighboring blocks. The memory 270 can store the reconstructed samples of the reconstructed blocks in the current picture and send them to the intra-frame predictor 222.

[0078] Figure 3is a diagram schematically illustrating a configuration of a video / image decoding device to which this document can be applied. Hereinafter, a decoding device may include an image decoding device and / or a video decoding device.

[0079] refer to Figure 3 , the video decoding device 300 may include an entropy decoder 310, a residual processor 320, a predictor 330, an adder 340, a filter 350, and a memory 360. The predictor 330 may include an inter-frame predictor 331 and an intra-frame predictor 332. The residual processor 320 may include a dequantizer 321 and an inverse transformer 322. According to an embodiment, the entropy decoder 310, the residual processor 320, the predictor 330, the adder 340, and the filter 350 described above may be composed of one or more hardware components (e.g., a decoder chipset or processor). In addition, the memory 360 may include a decoded picture buffer (DPB) and may be composed of a digital storage medium. The hardware components may also include the memory 360 as an internal / external component.

[0080] When a bit stream including video / image information is input, the decoding apparatus 300 can be used to decode the bit stream having been decoded. Figure 2 The image is reconstructed accordingly by processing the video / image information in the encoding device. For example, the decoding device 300 can derive the unit / block based on the information related to the block segmentation obtained from the bitstream. The decoding device 300 can perform decoding by using the processing unit applied in the encoding device. Therefore, the processing unit of decoding can be, for example, a coding unit, which can be divided from the coding tree unit or the maximum coding unit along the quadtree structure, the binary tree structure and / or the ternary tree structure. One or more transform units can be derived from the coding unit. The reconstructed image signal decoded and output by the decoding device 300 can be reproduced by a reproduction device.

[0081] The decoding device 300 may receive the data from the decoder in the form of a bit stream. Figure 2The received signal is output by the encoding device, and the entropy decoder 310 can decode the received signal. For example, the entropy decoder 310 can parse the bitstream to derive information required for image reconstruction (or picture reconstruction) (e.g., video / image information). The video / image information may also include information about various parameter sets such as the Adaptive Parameter Set (APS), Picture Parameter Set (PPS), Sequence Parameter Set (SPS), and Video Parameter Set (VPS). In addition, the video / image information may also include general constraint information. The decoding device can further decode the picture based on the information about the parameter sets and / or general constraint information. In this document, the information and / or syntax elements transmitted / received using signals and / or the syntax elements described later can be decoded and obtained from the bitstream through a decoding process. For example, the entropy decoder 310 can decode the information in the bitstream based on a coding method such as Exponential Golomb coding, CAVLC, CABAC, etc., and can output the values of the syntax elements required for image reconstruction and the quantized values of the transform coefficients of the residual. More specifically, the CABAC entropy decoding method can receive bins corresponding to each syntax element in the bitstream, use the decoded target syntax element information and the decoded information of the neighboring and decoded target blocks or the information of the symbol / bin decoded in the previous step to determine the context model, predict the bin generation probability based on the determined context model, and perform arithmetic decoding on the bin to generate the symbol corresponding to each syntax element value. Here, after determining the context model, the CABAC entropy decoding method can update the context model using the symbol / bin information decoded by the context model for the next symbol / bin. The information about prediction among the information decoded in the entropy decoder 310 can be provided to the predictor (inter-frame predictor 332 and intra-frame predictor 331), and the residual value (i.e., quantized transform coefficient) and associated parameter information for which entropy decoding has been performed in the entropy decoder 310 can be input to the residual processor 320. The residual processor 320 can derive a residual signal (residual block, residual sample, residual sample array). In addition, the information about filtering among the information decoded in the entropy decoder 310 can be provided to the filter 350. In addition, a receiver (not shown) that receives a signal output from the encoding device may also constitute the decoding device 300 as an internal / external element, and the receiver may be a component of the entropy decoder 310. In addition, the decoding device according to this document may be referred to as a video / image / picture decoding device, and the decoding device may be divided into an information decoder (video / image / picture information decoder) and a sample decoder (video / image / picture sample decoder). The information decoder may include the entropy decoder 310, and the sample decoder may include at least one of the dequantizer 321, the inverse transformer 322, the adder 340, the filter 350, the memory 360, the inter-frame predictor 332, and the intra-frame predictor 331.

[0082] The dequantizer 321 can output the transform coefficients by dequantizing the quantized transform coefficients. The dequantizer 321 can rearrange the quantized transform coefficients into a two-dimensional block. In this case, the rearrangement can be performed based on the order of coefficient scanning performed in the encoding device. The dequantizer 321 can dequantize the quantized transform coefficients using quantization parameters (e.g., quantization step size information) and obtain the transform coefficients.

[0083] The inverse transformer 322 obtains a residual signal (residual block, residual sample array) by performing inverse transformation on the transformation coefficients.

[0084] The predictor may perform prediction on the current block and generate a prediction block including prediction samples for the current block. The predictor may determine whether to apply intra prediction or inter prediction to the current block based on the information about prediction output from the entropy decoder 310, and specifically may determine the intra / inter prediction mode.

[0085] The predictor 320 can generate a prediction signal based on various prediction methods. For example, the predictor can apply intra prediction or inter prediction to predict a block, and can also apply intra prediction and inter prediction simultaneously. This can be referred to as combined inter and intra prediction (CIIP). In addition, the predictor can perform prediction on the block based on an intra block copy (IBC) prediction mode or a palette mode. The IBC prediction mode or palette mode can be used for content image / video coding such as games such as screen content coding (SCC). Although IBC essentially performs prediction in the current picture, its execution is similar to inter prediction in that it derives a reference block in the current picture. That is, IBC can use at least one of the inter prediction techniques described in this document. The palette mode can be considered an example of intra coding or intra prediction. When the palette mode is applied, information about the palette table and palette index can be included in the video / image information and signaled.

[0086] The intra-frame predictor 331 can predict the current block by referencing samples in the current picture. Depending on the prediction mode, the reference samples can be located near the current block or separated from the current block. In intra-frame prediction, the prediction mode can include multiple non-directional modes and multiple directional modes. The intra-frame predictor 331 can determine the prediction mode to be applied to the current block by using the prediction modes applied to neighboring blocks.

[0087] The inter-frame predictor 332 can derive a prediction block for the current block based on a reference block (reference sample array) specified by a motion vector in a reference picture. To reduce the amount of motion information transmitted in inter-frame prediction mode, motion information can be predicted on a block, sub-block, or sample basis based on the correlation of motion information between neighboring blocks and the current block. The motion information can include a motion vector and a reference picture index. The motion information can also include information about the inter-frame prediction direction (L0 prediction, L1 prediction, Bi prediction, etc.). In the case of inter-frame prediction, neighboring blocks can include spatially neighboring blocks in the current picture and temporally neighboring blocks in the reference picture. For example, the inter-frame predictor 332 can configure a motion information candidate list based on the neighboring blocks and derive the motion vector and / or reference picture index for the current block based on received candidate selection information. Inter-frame prediction can be performed based on various prediction modes, and information about the prediction can include information indicating the mode used for inter-frame prediction of the current block.

[0088] The adder 340 adds the obtained residual signal to the prediction signal (prediction block, prediction sample array) output from the predictor (inter-frame predictor 332 or intra-frame predictor 331), so that a reconstructed signal (reconstructed picture, reconstructed block, reconstructed sample array) can be generated. When there is no residual for the processing target block as in the case of applying skip mode, the prediction block can be used as the reconstructed block.

[0089] The adder 340 may be referred to as a reconstructor or a reconstructed block generator. The generated reconstructed signal may be used for intra prediction of the next block to be processed in the current picture, may be output through filtering as described below, or may be used for inter prediction of the next picture.

[0090] In addition, luma mapping and chroma scaling (LMCS) can be applied to the picture decoding process.

[0091] The filter 350 can improve the subjective / objective image quality by applying filtering to the reconstructed signal. For example, the filter 350 can generate a modified reconstructed image by applying various filtering methods to the reconstructed image, and store the modified reconstructed image in the memory 360, specifically, in the DPB of the memory 360. Various filtering methods may include, for example, deblocking filtering, sample adaptive offset, adaptive loop filter, bilateral filter, etc.

[0092] The (modified) reconstructed picture stored in the DPB of the memory 360 can be used as a reference picture in the inter-frame predictor 332. The memory 360 can store the motion information of the block from which the motion information in the current picture is derived (or decoded) and / or the motion information of the block in the reconstructed picture. The stored motion information can be sent to the inter-frame predictor 332 to be used as the motion information of the spatially adjacent block or the motion information of the temporally adjacent block. The memory 360 can store the reconstructed samples of the reconstructed block in the current picture and transmit the reconstructed samples to the intra-frame predictor 331.

[0093] In the present disclosure, the embodiments described in the filter 260, the inter-frame predictor 221, and the intra-frame predictor 222 of the encoding device 200 may be the same as the filter 350, the inter-frame predictor 332, and the intra-frame predictor 331 of the decoding device 300 or may be applied corresponding to the filter 350, the inter-frame predictor 332, and the intra-frame predictor 331 of the decoding device 300, respectively.

[0094] As described above, when performing video coding, prediction is performed to improve compression efficiency. A prediction block including prediction samples for a current block, i.e., a target coding block, can be generated by prediction. In this case, the prediction block includes prediction samples in the spatial domain (or pixel domain). The prediction block is derived similarly in the encoding device and the decoding device. The encoding device can improve image coding efficiency by signaling information (residual information) about the residual between the original block, rather than the original sample values of the original block themselves, and the prediction block, to the decoding device. The decoding device can derive a residual block including residual samples based on the residual information, can generate a reconstructed block including reconstructed samples by adding the residual block to the prediction block, and can generate a reconstructed picture including the reconstructed block.

[0095] Residual information can be generated through a transformation and quantization process. For example, the encoding device can derive a residual block between the original block and the prediction block, derive transform coefficients by performing a transformation process on the residual samples (residual sample array) included in the residual block, derive quantized transform coefficients by performing a quantization process on the transform coefficients, and can signal the relevant residual information to the decoding device (via a bitstream). In this case, the residual information may include information such as value information, position information, a transformation scheme, a transform kernel, and a quantization parameter for the quantized transform coefficients. The decoding device can perform a dequantization / inverse transformation process based on the residual information and derive residual samples (or residual blocks). The decoding device can generate a reconstructed picture based on the prediction block and the residual block. In addition, the encoding device can derive a residual block for inter-frame prediction reference of a subsequent picture by dequantizing / inverse transforming the quantized transform coefficients, and can generate a reconstructed picture.

[0096] Intra-frame prediction may indicate the generation of prediction samples for the current block based on reference samples in the picture to which the current block belongs (hereinafter referred to as the current picture). When intra-frame prediction is applied to the current block, neighboring reference samples to be used for intra-frame prediction of the current block may be derived. The neighboring reference samples of the current block may include a total of 2xnH samples, which are samples adjacent to the left boundary of the current block (nWxnH) and samples adjacent to the upper left corner of the current block (nWxnH), a total of 2xnH samples, which are samples adjacent to the upper boundary of the current block and samples adjacent to the upper right corner of the current block, and one sample adjacent to the upper left corner of the current block. Alternatively, the neighboring reference samples of the current block may include multiple columns of upper neighboring samples and multiple rows of left neighboring samples. Furthermore, the neighboring reference samples of the current block may include a total of nH samples adjacent to the right boundary of the current block (nWxnH), a total of nW samples adjacent to the lower boundary of the current block, and one sample adjacent to the lower right corner of the current block.

[0097] However, some of the neighboring reference samples of the current block have not yet been decoded or may be unavailable. In this case, the decoding device can construct neighboring reference samples to be used for prediction by replacing unavailable samples with available samples. Alternatively, the neighboring reference samples to be used for prediction can be configured by interpolation of available samples.

[0098] If neighboring reference samples are derived, (i) the prediction sample may be derived based on an average or interpolation of neighboring reference samples of the current block, and (ii) the prediction sample may be derived based on reference samples existing in a specific (prediction) direction with respect to the prediction sample among the neighboring reference samples of the current block. The case of (i) may be referred to as a non-directional mode or a non-angular mode, and the case of (ii) may be referred to as a directional mode or an angular mode.

[0099] Alternatively, the prediction sample may be generated by interpolating the first neighboring sample located in the prediction direction of the intra prediction mode of the current block and the second neighboring sample located in the opposite direction of the prediction direction based on the prediction sample of the current block among the neighboring reference samples. This may be referred to as linear interpolation intra prediction (LIP). Furthermore, a linear model may be used to generate chroma prediction samples based on luma samples. This may be referred to as LM mode or CCLM (chroma component LM) mode.

[0100] In addition, the temporary prediction sample of the current block can be derived based on the filtered neighboring reference samples, and the prediction sample of the current block can be derived by weighted summing at least one reference sample derived from the normal neighboring reference samples (i.e., the unfiltered neighboring reference samples) according to the intra prediction mode and the temporary prediction sample. The aforementioned situation may be referred to as position-dependent intra prediction (PDPC).

[0101] In addition, a prediction sample can be derived using a reference sample in a prediction direction located in a corresponding line by selecting a reference sample line with the highest prediction accuracy among multiple reference sample lines adjacent to the current block, and intra-frame prediction encoding can be performed by indicating (signaling) the reference sample line used at this time to a decoding device. The aforementioned case may be referred to as multiple reference line (MRL) intra-frame prediction or MRL-based intra-frame prediction.

[0102] In addition, intra prediction can be performed based on the same intra prediction mode by dividing the current block into vertical or horizontal sub-partitions, and neighboring reference samples can be derived and used in units of sub-partitions. That is, in this case, the intra prediction mode used for the current block is equally applied to the sub-partitions, and neighboring reference samples can be derived and used in units of sub-partitions, thereby enhancing intra prediction performance in some cases. This prediction method may be referred to as intra sub-partition (ISP) intra prediction or ISP-based intra prediction.

[0103] The aforementioned intra-frame prediction method may be referred to as an intra-frame prediction type separate from the intra-frame prediction mode. The intra-frame prediction type may be referred to by various terms such as intra-frame prediction technology or additional intra-frame prediction mode. For example, the intra-frame prediction type (or additional intra-frame prediction mode, etc.) may include at least one of the aforementioned LIP, PDPC, MRL, and ISP. A general intra-frame prediction method different from a specific intra-frame prediction type such as LIP, PDPC, MRL, and ISP may be referred to as a normal intra-frame prediction type. If a specific intra-frame prediction type is not applied, a normal intra-frame prediction type may generally be applied, and prediction may be performed based on the aforementioned intra-frame prediction mode. At the same time, if necessary, post-processing filtering may also be performed on the derived prediction samples.

[0104] Specifically, the intra prediction process may include an intra prediction mode / type determination step, a neighboring reference sample derivation step, and a prediction sample derivation step based on the intra prediction mode / type. In addition, if necessary, a post-filtering step may be performed on the derived prediction samples.

[0105] Furthermore, among the intra prediction modes, the non-directional mode (or non-angular mode) is a DC mode based on an average value of neighboring reference samples of a current block or a planar mode based on interpolation of neighboring reference samples.

[0106] When inter-frame prediction is applied, the predictor of the encoding / decoding device can derive prediction samples by performing inter-frame prediction on a block-by-block basis. Inter-frame prediction can be applied when performing prediction on the current block. That is, the predictor of the encoding / decoding device (more specifically, the inter-frame predictor) can derive prediction samples by performing inter-frame prediction on a block-by-block basis. Inter-frame prediction can refer to predictions derived using a method that relies on data elements (e.g., sample values or motion information) from pictures other than the current picture. When inter-frame prediction is applied to the current block, the prediction block (prediction sample array) for the current block can be derived based on a reference block (reference sample array) specified by a motion vector in a reference picture indicated by a reference picture index. In this case, to reduce the amount of motion information transmitted in inter-frame prediction mode, the motion information of the current block can be predicted on a block, sub-block, or sample basis based on the correlation of motion information between neighboring blocks and the current block. The motion information can include a motion vector and a reference picture index. The motion information can further include information on the inter-frame prediction type (L0 prediction, L1 prediction, Bi prediction, etc.). When inter-frame prediction is applied, neighboring blocks may include spatially neighboring blocks in the current picture and temporally neighboring blocks in a reference picture. The reference picture including the reference block and the reference picture including the temporally neighboring block may be the same as or different from each other. Temporally neighboring blocks may be referred to as collocated reference blocks, collocated CUs (colCUs), etc., and the reference picture including the temporally neighboring blocks may be referred to as collocated pictures (colPics). For example, a motion information candidate list may be configured based on the neighboring blocks of the current block, and a flag or index information indicating which candidate is selected (used) to derive the motion vector and / or reference picture index of the current block may be signaled. Inter-frame prediction can be performed based on various prediction modes. For example, in skip mode and merge mode, the motion information of the current block may be the same as that of the selected neighboring block. In skip mode, unlike merge mode, a residual signal may not be transmitted. In motion vector prediction (MVP) mode, the motion vector of the selected neighboring block may be used as a motion vector predictor, and the motion vector difference may be signaled. In this case, the motion vector of the current block may be derived by using the sum of the motion vector predictor and the motion vector difference.

[0107] The motion information may further include L0 motion information and / or L1 motion information according to the inter-frame prediction type (L0 prediction, L1 prediction, Bi prediction, etc.). The L0-direction motion vector may be referred to as the L0 motion vector or MVL0, while the L1-direction motion vector may be referred to as the L1 motion vector or MVL1. Prediction based on the L0 motion vector may be referred to as L0 prediction, prediction based on the L1 motion vector may be referred to as L1 prediction, and prediction based on both the L0 motion vector and the L1 motion vector may be referred to as bidirectional prediction. Here, the L0 motion vector may indicate a motion vector associated with reference picture list L0, and the L1 motion vector may indicate a motion vector associated with reference picture list L1. Reference picture list L0 may include pictures preceding the current picture in output order, and reference picture list L1 may include pictures following the current picture in output order as reference pictures. The preceding picture may be referred to as a forward (reference) picture, and the subsequent picture may be referred to as a backward (reference) picture. Reference picture list L0 may further include pictures following the current picture in output order as reference pictures. In this case, the previous picture can be indexed first in the reference picture list L0, and then the subsequent picture can be indexed. The reference picture list L1 can further include pictures that precede the current picture in the output order as reference pictures. In this case, the subsequent picture can be indexed first in the reference picture list L1, and then the previous picture can be indexed. Here, the output order can correspond to the picture order count (POC) order.

[0108] Figure 4 Illustrated is an example of an illustrative video / image encoding method to which embodiments of this document are applicable.

[0109] Figure 4 The method disclosed in the above Figure 2 Specifically, S400 may be performed by the inter-frame predictor 221 or the intra-frame predictor 222 of the encoding device 200, and S410, S420, S430, and S440 may be performed by the subtractor 231, the transformer 232, the quantizer 233, and the entropy encoder 240 of the encoding device 200.

[0110] refer to Figure 4 , the encoding device may derive a prediction sample through prediction for the current block (S400). The encoding device may determine whether to perform inter-frame prediction or intra-frame prediction on the current block, and may determine a specific inter-frame prediction mode or a specific intra-frame prediction mode based on the RD cost. According to the determined mode, the encoding device may derive a prediction sample for the current block.

[0111] The encoding apparatus may derive residual samples by comparing predicted samples and original samples for the current block ( S410 ).

[0112] The encoding apparatus may derive transform coefficients through a transform process for the residual sample ( S420 ), and derive quantized transform coefficients by quantizing the derived transform coefficients ( S430 ).

[0113] The encoding device may encode image information including prediction information and residual information, and may output the encoded image information in the form of a bitstream (S440). The prediction information is information related to the prediction process and may include prediction mode information and motion information (for example, when inter-frame prediction is applied). The residual information may include information about quantized transform coefficients. The residual information may be entropy coded.

[0114] The output bitstream may be delivered to a decoding device via a storage medium or a network.

[0115] Figure 5 An example of an exemplary video / image decoding method to which the embodiments of the present disclosure are applicable is shown.

[0116] exist Figure 5 The method disclosed in the above Figure 3 The decoding device 300 of FIG5 is executed. Specifically, S500 may be executed by the inter-frame predictor 332 or the intra-frame predictor 331 of the decoding device 300. The process of deriving the value of the relevant syntax element by decoding the prediction information included in the bitstream in S500 may be executed by the entropy decoder 310 of the decoding device 300. S510, S520, S530, and S540 may be executed by the entropy decoder 310, the dequantizer 321, the inverse transformer 322, and the adder 340 of the decoding device 300, respectively.

[0117] refer to Figure 5 The decoding apparatus may perform an operation corresponding to the operation performed by the encoding apparatus. The decoding apparatus may perform inter-frame prediction or intra-frame prediction on the current block based on the received prediction information and derive a prediction sample (S500).

[0118] The decoding apparatus may derive a quantized transform coefficient for the current block based on the received residual information (S510).The decoding apparatus may derive the quantized transform coefficient from the residual information through entropy decoding.

[0119] The decoding apparatus may dequantize the quantized transform coefficient to derive a transform coefficient ( S520 ).

[0120] The decoding apparatus derives residual samples through an inverse transform process for the transform coefficients ( S530 ).

[0121] The decoding apparatus may generate reconstructed samples for the current block based on the prediction samples and the residual samples, and generate a reconstructed picture based thereon (S540). As described above, the in-loop filtering process may be further applied to subsequent reconstructed pictures.

[0122] Figure 6 The intra prediction process is exemplarily shown. Figure 6 The intra prediction process disclosed in can be applied to the above Figure 4 and Figure 5 The illustrated prediction process (when intra prediction mode is applied).

[0123] refer to Figure 6 As described above, the intra prediction process may include the steps of determining an intra prediction mode / type, deriving neighboring reference samples, and performing intra prediction (generating prediction samples). The intra prediction process may be performed in the encoding apparatus and decoding apparatus described above. In this document, a coding device may include an encoding apparatus and / or a decoding apparatus.

[0124] The coding apparatus may determine an intra prediction mode / type ( S600 ).

[0125] The encoding device may determine the intra-frame prediction mode / type applied to the current block from the various intra-frame prediction modes / types described above, and may generate prediction-related information. The prediction-related information may include intra-frame prediction mode information indicating the intra-frame prediction mode applied to the current block and / or intra-frame prediction type information indicating the intra-frame prediction type applied to the current block. The decoding device may determine the intra-frame prediction mode / type applied to the current block based on the prediction-related information.

[0126] Here, the intra prediction mode information may include, for example, flag information (e.g., intra_luma_mpm_flag) indicating whether the most probable mode (MPM) is applied to the current block or the residual mode is applied. When MPM is applied to the current block, the prediction mode information may further include index information (e.g., intra_luma_mpm_idx) indicating one of the intra prediction mode candidates (MPM candidates). The intra prediction mode candidate (MPM candidate) may consist of an MPM candidate list or an MPM list. In addition, when MPM is not applied to the current block, the intra prediction mode information may further include residual mode information (e.g., intra_luma_mpm_remainder) indicating one of the remaining intra prediction modes other than the intra prediction mode candidate (MPM candidate). The decoding device may determine the intra prediction mode of the current block based on the intra prediction mode information.

[0127] In addition, the intra prediction type information can be implemented in various forms. As an example, the intra prediction type information may include intra prediction type index information indicating one of the intra prediction types. As another example, the intra prediction type information may include reference sample line information (e.g., intra_luma_ref_idx) indicating whether MRL is applied to the current block and, when applied, which reference sample line is used, and ISP flag information indicating whether ISP is applied to the current block (e.g., intra_subpartitions_mode_flag), ISP type information indicating the split type of the sub-partition when ISP is applied (e.g., intra_subpartitions_split_flag), flag information indicating whether PDCP is applied, or flag information indicating whether LIP is applied. In addition, the intra prediction type information may include a MIP flag indicating whether matrix-based intra prediction (MIP) is applied to the current block.

[0128] For example, when intra prediction is applied, the intra prediction mode applied to the current block can be determined by using the intra prediction mode of the neighboring blocks. For example, the coding device can select one of the MPM candidates in the MPM (Most Probable Mode) list based on the received MPM index, which is derived based on the intra prediction modes of the neighboring blocks (e.g., left and / or above neighboring blocks) of the current block and additional candidate modes, or can select one of the remaining intra prediction modes not included in the MPM candidates (and planar mode) based on the remaining intra prediction mode information. The MPM list can be configured to include or exclude planar mode as a candidate. For example, when the MPM list includes planar mode as a candidate, the MPM list can have 6 candidates, and when the MPM list does not include planar mode as a candidate, the MPM list can have 5 candidates. When the MPM list does not include planar mode as a candidate, a non-planar flag (e.g., intra_luma_not_planar_flag) indicating whether the intra prediction mode of the current block is not a planar mode can be signaled. For example, the MPM flag may be signaled first, and the MPM index and the non-planar flag may be signaled when the value of the MPM flag is 1. Furthermore, the MPM index may be signaled when the value of the non-planar flag is 1. Here, the reason why the MPM list is configured to exclude the planar mode as a candidate is that the planar mode is always considered as the MPM, so by first signaling the flag (non-planar flag), it is checked whether the MPM is in the planar mode, rather than saying that the planar mode is not the MPM.

[0129] For example, it can be indicated based on an MPM flag (e.g., intra_luma_mpm_flag) whether the intra prediction mode applied to the current block is among the MPM candidates (and planar mode) or among the remaining modes. An MPM flag value of 1 can indicate that the intra prediction mode for the current block is within the MPM candidates (and planar mode), while an MPM flag value of 0 can indicate that the intra prediction mode for the current block is not within the MPM candidates (and planar mode). A non-planar flag (e.g., intra_luma_not_planar_flag) value of 0 can indicate that the intra prediction mode for the current block is planar mode, and a non-planar flag value of 1 can indicate that the intra prediction mode for the current block is not planar mode. The MPM index can be signaled in the form of an mpm_idx or intra_luma_mpm_idx syntax element, and the remaining intra prediction mode information can be signaled in the form of a rem_intra_luma_pred_mode or intra_luma_mpm_remainder syntax element. For example, the remaining intra prediction mode information may indicate one of the remaining intra prediction modes that is not included in the MPM candidates (and planar mode) among all intra prediction modes by indexing in order of the prediction mode number. The intra prediction mode may be an intra prediction mode of a luminance component (sample). Hereinafter, the intra prediction mode information may include at least one of an MPM flag (e.g., intra_luma_mpm_flag), a non-planar flag (e.g., intra_luma_not_planar_flag), an MPM index (e.g., mpm_idx or intra_luma_mpm_idx), and remaining intra prediction mode information (rem_intra_luma_pred_mode or intra_luma_mpm_remainder). In this document, the MPM list may be referred to by a variety of terms such as MPM candidate list and candModeList.

[0130] When a MIP is applied to the current block, a separate mpm flag (e.g., intra_mip_mpm_flag), an mpm index (e.g., intra_mip_mpm_idx), and remaining intra prediction mode information (e.g., intra_mip_mpm_remainder) for the MIP may be separately signaled, and the non-planar flag may not be signaled.

[0131] In other words, when an image is divided into blocks, the current block to be coded and the neighboring blocks generally have similar image characteristics. Therefore, there is a high probability that the current block and the neighboring blocks have the same or similar intra-prediction modes. Therefore, the encoding apparatus can use the intra-prediction modes of the neighboring blocks to encode the intra-prediction mode of the current block.

[0132] As described above, when the intra prediction mode applied to the current block is determined using the intra prediction mode of the neighboring block, the coding device may configure a most probable mode (MPM) list for the current block. The MPM list may be referred to as an MPM candidate list. Here, MPM may refer to a mode for improving coding efficiency by considering the similarity between the current block and the neighboring block during intra prediction mode coding. As described above, the MPM list may be configured to include a planar mode, or may be configured to exclude a planar mode. For example, when the MPM list includes a planar mode, the number of candidates in the MPM list may be six. And, when the MPM list does not include a planar mode, the number of candidates in the MPM list may be five.

[0133] The encoding device may perform prediction based on various intra prediction modes and may determine the optimal intra prediction mode based on rate-distortion optimization (RDO). In this case, the encoding device may determine the optimal intra prediction mode using only the planar mode and the MPM candidates configured in the MPM list, or may further use the remaining intra prediction modes as well as the planar mode and the MPM candidates configured in the MPM list to determine the optimal intra prediction mode. Specifically, for example, if the intra prediction type of the current block is a specific type other than the normal intra prediction type (e.g., LIP, MRL, or ISP), the encoding device may determine the optimal intra prediction mode by considering only the MPM candidates and the planar mode as intra prediction mode candidates for the current block. That is, in this case, the intra prediction mode for the current block may be determined only from the MPM candidates and the planar mode, and in this case, encoding / signaling of the mpm flag may not be performed. In this case, the decoding device may infer that the mpm flag is 1 without separately receiving a signal of the mpm flag.

[0134] Meanwhile, typically, when the intra prediction mode of the current block is not a planar mode and is one of the MPM candidates in the MPM list, the encoding apparatus generates an mpm index (mpm idx) indicating one of the MPM candidates. Alternatively, if the intra prediction mode of the current block is not in the MPM list, the encoding apparatus generates MPM residual information (remaining intra prediction mode information) indicating the same mode as the intra prediction mode of the current block among the remaining intra prediction modes not included in the MPM list (and planar mode). The MPM residual information may include, for example, the intra_luma_mpm_remainder syntax element.

[0135] The decoding device obtains intra-frame prediction mode information from the bitstream. As described above, the intra-frame prediction mode information may include at least one of an MPM flag, a non-planar flag, an MPM index, and MPM residual information (residual intra-frame prediction mode information). The decoding device may configure an MPM list. The MPM list is configured in the same manner as the MPM list configured in the encoding device. That is, the MPM list may include intra-frame prediction modes of neighboring blocks and may further include a specific intra-frame prediction mode according to a predetermined method.

[0136] The decoding device may determine the intra prediction mode of the current block based on the MPM list and the intra prediction mode information. For example, when the value of the MPM flag is 1, the decoding device may derive the planar mode as the intra prediction mode of the current block (based on the non-planar flag) or may derive the candidate indicated by the MPM index from the MPM candidates in the MPM list as the intra prediction mode of the current block. Here, the MPM candidate may indicate only the candidates included in the MPM list, or may include not only the candidates included in the MPM list but also the planar mode applicable when the value of the MPM flag is 1.

[0137] As another example, when the value of the MPM flag is 0, the decoding apparatus may derive the intra prediction mode indicated by the remaining intra prediction mode information (which may be referred to as MPM residual information) among the remaining intra prediction mode information not included in the MPM list and the planar mode as the intra prediction mode of the current block. Meanwhile, as another example, when the intra prediction type of the current block is a specific type (e.g., LIP, MRL, or ISP, etc.), the decoding apparatus may derive the candidate indicated by the MPM flag in the MPM list or the planar mode as the intra prediction mode of the current block without parsing / decoding / checking the MPM flag.

[0138] The coding apparatus may derive neighboring reference samples of a current block ( S610 ).

[0139] When intra prediction is applied to a current block, neighboring reference samples to be used for intra prediction of the current block may be derived. The neighboring reference samples of the current block may include a total of 2xnH samples, which are samples adjacent to the lower left corner and the left boundary of the current block (nWxnH in size), a total of 2xnW samples, which are samples adjacent to the upper boundary of the current block and adjacent to the upper right corner of the current block, and one sample adjacent to the upper left corner of the current block. Alternatively, the neighboring reference samples of the current block may include multiple columns of upper neighboring samples and multiple rows of left neighboring samples. Furthermore, the neighboring reference samples of the current block may include a total of nH samples adjacent to the right boundary of the current block (nWxnH in size), a total of nW samples adjacent to the lower boundary of the current block, and one sample adjacent to the lower right corner of the current block.

[0140] On the other hand, when MRL is applied (i.e., when the value of the MRL index is greater than 0), the neighboring reference samples may be located in rows 1 and 2 instead of row 0 adjacent to the current block on the left / upper side. In this case, the number of neighboring reference samples can be further increased. At the same time, when ISP is applied, the neighboring reference samples can be derived in units of sub-partitions.

[0141] The coding apparatus may derive a prediction sample by performing intra prediction on the current block ( S620 ).

[0142] The coding device may derive prediction samples based on the intra prediction mode / type and neighboring samples. The coding device may derive reference samples according to the intra prediction mode of the current block from among the neighboring reference samples of the current block, and may derive prediction samples of the current block based on the reference samples.

[0143] Figure 7 The inter-frame prediction process is exemplarily shown. Figure 7 The inter-frame prediction process disclosed in can be applied to the above Figure 4 and Figure 5 The prediction process shown in (when inter prediction mode is applied).

[0144] refer to Figure 7 As described above, the inter-frame prediction process may include an inter-frame prediction mode determination step, a motion information derivation step based on the determined prediction mode, and a prediction process (prediction sample generation) step based on the derived motion information. As described above, the inter-frame prediction process may be performed by an encoding device and a decoding device. In this document, a coding device may include an encoding device and / or a decoding device.

[0145] The coding apparatus may determine an inter prediction mode for a current block ( S700 ).

[0146] Various inter-frame prediction modes can be used to predict the current block in the picture. For example, various modes such as merge mode, skip mode, motion vector prediction (MVP) mode, affine mode, sub-block merge mode, merge with MVD (MMVD) mode and historical motion vector prediction (HMVP) mode can be used. Decoder-side motion vector refinement (DMVR) mode, adaptive motion vector resolution (AMVR) mode, bidirectional prediction with CU-level weights (BCW), bidirectional optical flow (BDOF), etc. can be further used as additional modes. Affine mode can also be referred to as affine motion prediction mode. MVP mode can also be referred to as advanced motion vector prediction (AMVP) mode. In this document, some modes and / or motion information candidates derived from some modes can also be included in one of the motion information-related candidates in other modes. For example, an HMVP candidate can be added to the merge candidate of the merge / skip mode, or can also be added to the MVP candidate of the MVP mode. If the HMVP candidate is used as a motion information candidate for the merge mode or skip mode, the HMVP candidate can be referred to as an HMVP merge candidate.

[0147] Prediction mode information indicating the inter-frame prediction mode of the current block can be sent from the encoding device to the decoding device by signaling. In this case, the prediction mode information can be included in the bitstream and received by the decoding device. The prediction mode information may include index information indicating one of a plurality of candidate modes. Alternatively, the inter-frame prediction mode may be indicated by hierarchical signaling of flag information. In this case, the prediction mode information may include one or more flags. For example, whether the skip mode is applied may be indicated by signaling a skip flag, whether the merge mode is applied may be indicated by signaling a merge flag when the skip mode is not applied, and whether the MVP mode is applied or when the merge mode is not applied may be further signaled for additional distinction. The affine mode may be signaled as an independent mode or as a subordinate mode with respect to the merge mode or the MVP mode. For example, the affine mode may include an affine merge mode and an affine MVP mode.

[0148] The coding apparatus may derive motion information for a current block ( S710 ).

[0149] Here, motion information may be derived based on the inter prediction mode.

[0150] The coding device may use the motion information of the current block to perform inter-frame prediction. The encoding device may derive the optimal motion information for the current block through a motion estimation process. For example, the encoding device may search for a similar reference block with high correlation in units of fractional pixels within a predetermined search range in a reference picture using the original block in the original picture for the current block, and derive motion information from the searched reference block. The similarity of the blocks may be derived based on the difference in sample values based on the phase. For example, the similarity of the blocks may be calculated based on the sum of absolute differences (SAD) between the current block (or the template of the current block) and the reference block (or the template of the reference block). In this case, the motion information may be derived based on the reference block with the smallest SAD in the search area. The derived motion information may be signaled to the decoding device according to various methods based on the inter-frame prediction mode.

[0151] The coding apparatus may perform inter prediction based on motion information for the current block ( S720 ).

[0152] The coding device may derive a prediction sample for the current block based on the motion information. The current block including the prediction sample may be referred to as a prediction block.

[0153] Meanwhile, as described above, the quantizer of the encoding device may apply quantization to the transform coefficient to derive the quantized transform coefficient, and the dequantizer of the encoding device or the dequantizer of the decoding device may derive the transform coefficient by applying dequantization to the quantized transform coefficient.

[0154] Typically, in video / image coding, the quantization rate can be changed, and compression can be adjusted using the changed quantization rate. From an implementation perspective, a quantization parameter (QP) can be used instead of directly using the quantization rate, taking into account complexity. For example, a quantization parameter with an integer value of 0 to 63 can be used, and each quantization parameter value can correspond to an actual quantization rate. The quantization parameter (QP) for the luminance component (luminance samples) is the quantization parameter of the luminance component. Y ) and the quantization parameter (QP) for the chroma components (chroma samples) C ) can be set differently.

[0155] The quantization process takes the transform coefficient (C) as input and divides it by the quantization rate (Qstep) to obtain a quantized transform coefficient (C') based thereon. In this case, considering the computational complexity, the quantization rate is multiplied by the scaling to form an integer, and a shift operation can be performed by a value corresponding to the scaling value. The quantization scale can be derived based on the product of the quantization rate and the scaling value. In other words, the quantization scale can be derived based on the QP. The quantization scale can be applied to the transform coefficient (C) to derive the quantized transform coefficient (C') based thereon.

[0156] The dequantization process is the inverse process of the quantization process, and the quantized transform coefficient (C') is multiplied by the quantization rate (Qstep), and based on this, the reconstructed transform coefficient (C") can be obtained. In this case, the level scale can be derived according to the quantization parameter, and the level scale can be applied to the quantized transform coefficient (C') to derive the reconstructed transform coefficient (C") based on this. Due to losses in the transformation and / or quantization process, the reconstructed transform coefficient (C") may be slightly different from the original transform coefficient (C). Therefore, the encoding device performs dequantization in the same manner as the decoding device.

[0157] In addition, an adaptive frequency-weighted quantization technique that adjusts the quantization strength according to frequency can be applied. Adaptive frequency-weighted quantization is a method that applies different quantization strengths to each frequency. Adaptive frequency-weighted quantization can use a predefined quantization scaling matrix to apply different quantization strengths to each frequency. That is, the above-mentioned quantization / dequantization process can be further performed based on the quantization scaling matrix. For example, different quantization scaling matrices can be used to generate the residual signal of the current block based on the size of the current block and / or whether the prediction mode applied to the current block is inter-frame prediction or intra-frame prediction. The quantization scaling matrix can be referred to as a quantization matrix or a scaling matrix. The quantization scaling matrix can be predefined. In addition, for frequency-adaptive scaling, frequency quantization scaling information about the quantization scaling matrix can be configured / encoded in the encoding device and sent to the decoding device using a signal. The frequency quantization scaling information can be referred to as quantization scaling information. The frequency quantization scaling information can include scaling list data (scaling_list_data). The quantization scaling matrix can be derived (modified) based on the scaling list data. In addition, the frequency quantization scaling information can include presence flag information indicating whether the scaling list data exists. Alternatively, when the zoom list data is signaled at a higher level (eg, SPS), information indicating whether the zoom list data is modified at a lower level (eg, PPS or tile group header, etc.) may be further included.

[0158] As described above, scaling list data may be signaled to indicate a (frequency-based quantization) scaling matrix to use for quantization / dequantization.

[0159] Signaling support for default and user-defined scaling matrices exists in the HEVC standard and is currently adopted in the VVC standard. However, for the VVC standard, additional support for signaling of the following functionality has been incorporated.

[0160] -Three modes of scaling matrix: OFF, DEFAULT, USER_DEFINED

[0161] - Larger block size range (4x4 to 64x64 for luma, 2x2 to 32x32 for chroma)

[0162] -Rectangular Transform Block (TB)

[0163] -Related quantification

[0164] -Multiple Transform Selection (MTS)

[0165] - Large transforms that zero out high frequency coefficients

[0166] -Intra-frame sub-block partitioning (ISP)

[0167] - Intra Block Copy (IBC) (also known as Current Picture Reference (CPR))

[0168] - Default scaling matrix for all TB sizes, default value is 16

[0169] It should be noted that the scaling matrix should not be applied to all sizes of transform skip (TS) and secondary transform (ST).

[0170] In the following, the high-level syntax (HSL) structure for supporting scaling lists in the VVC standard will be described in detail. First, a flag can be signaled via a sequence parameter set (SPS) to indicate that scaling lists are available for the currently coded video sequence (CVS) being decoded. Then, if the flag is available, additional flags can be parsed to indicate whether specific data is present in the scaling list of the SPS. This can be shown in Table 1.

[0171] Table 1 is an excerpt from the SPS to describe the scaling list of CVS.

[0172] [Table 1]

[0173]

[0174] The semantics of the syntax elements included in the SPS syntax of Table 1 can be shown in Table 2 below.

[0175] [Table 2]

[0176]

[0177] With reference to Tables 1 and 2 above, a scaling_list_enabled_flag may be signaled from the SPS. For example, if the value of scaling_list_enabled_flag is 1, it may indicate that a scaling list is used in the scaling process of the transform coefficients, and if the value of scaling_list_enabled_flag is 0, it may indicate that a scaling list is not used in the scaling process of the transform coefficients. In this case, when the value of scaling_list_enabled_flag is 1, sps_scaling_list_data_present_flag may be further signaled from the SPS. For example, when the value of sps_scaling_list_data_present_flag is 1, it may indicate that a scaling_list_data() syntax structure is present in the SPS, and when the value of sps_scaling_list_data_present_flag is 0, it may indicate that a scaling_list_data() syntax structure is not present in the SPS. If sps_scaling_list_data_present_flag is not present, the value of sps_scaling_list_data_present_flag may be inferred to be 0.

[0178] In addition, a flag (e.g., pps_scaling_list_data_present_flag) may be parsed first in the picture parameter set (PPS). If this flag is available, scaling_list_data() may be parsed in the PPS. If scaling_list_data() is initially present in the SPS and later parsed in the PPS, the data in the PPS may take precedence over the data in the SPS. Table 3 below is an excerpt from the PPS to describe the scaling list data.

[0179] [Table 3]

[0180]

[0181] The semantics of the syntax elements included in the PPS syntax of Table 3 can be shown in Table 4 below.

[0182] [Table 4]

[0183]

[0184] Referring to Tables 3 and 4, pps_scaling_list_data_present_flag may be signaled from the PPS. For example, when the value of pps_scaling_list_data_present_flag is 1, it may indicate that the scaling list data used for the picture referring to the PPS is derived based on the scaling list specified by the active SPS and the scaling list specified by the PPS. When the value of pps_scaling_list_data_present_flag is 0, it may indicate that the scaling list data used for the picture referring to the PPS is inferred to be the same as the scaling list specified by the active SPS. At this time, when the value of scaling_list_enabled_flag is 0, the value of pps_scaling_list_data_present_flag should be 0. When the value of scaling_list_enabled_flag is 1, the value of sps_scaling_list_data_present_flag is 0, and the value of pps_scaling_list_data_present_flag is 0, the default scaling list data may be used to derive the scan factor as described in the scaling list data semantics.

[0185] A scaling list can be defined for the following quantization matrix sizes in the VVC standard. This can be shown in Table 5 below. The supported range of quantization matrices has been extended to include 2x2 and 64x64 in the HEVC standard as well as 4x4, 8x8, 16x16, and 32x32.

[0186] [Table 5]

[0187] The size of the quantization matrix sizeId 1x1 0 2x2 1 4x4 2 8x8 3 16x16 4 32x32 5 64x64 6

[0188] Table 5 defines the sizeId of all used quantization matrix sizes. The above combination can be used to assign matrixId to different combinations of sizeId, prediction mode (CuPredMode) of the coding unit and color component. The CuPredMode that can be considered here can be inter-frame, intra-frame and IBC (intra-frame block copy). Intra-frame mode and IBC mode can be treated equally. Therefore, the same matrixId can be shared for a given color component. Here, the color components that can be considered can be brightness (Luma (Y)) and two color components (Cb and Cr). The allocated matrixId can be represented as shown in Table 6 below.

[0189] Table 6 shows matrixId according to sizeId, prediction mode, and color component.

[0190] [Table 6]

[0191]

[0192]

[0193] Table 7 below shows an example of a syntax structure for scaling list data (eg, scaling_list_data()).

[0194] [Table 7]

[0195]

[0196]

[0197] The semantics of the syntax elements included in the syntax of Table 7 can be shown in Table 8 below.

[0198] [Table 8]

[0199]

[0200]

[0201] Referring to Tables 7 and 8, to extract scaling list data (e.g., scaling_list_data()), for all sizeIds from 1 to 6 and matrixIds from 0 to 5, the scaling list data can be applied to 2x2 chroma components and 64x64 luma components. Then, a flag (e.g., scaling_list_pred_mode_flag) can be parsed to indicate whether the value of the scaling list is the same as that of the reference scaling list. The reference scaling list can be represented by scaling_list_pred_matrix_id_delta[sizeId][matrixId]. However, when scaling_list_pred_mode_flag[sizeId][matrixId] is 1, the scaling list data can be explicitly signaled. When scaling_list_pred_matrix_id_delta is 0, the DEFAULT mode with default values can be used, as shown in Tables 9 to 12. For other values of scaling_list_pred_matrix_id_delta, as shown in the semantics of Table 8, refMatrixId may be determined first.

[0202] In explicit signaling, i.e., in USER_DEFINED mode, the maximum number of coefficients to be signaled can be determined first. For quantization block sizes of 2x2, 4x4, and 8x8, all coefficients can be signaled. For sizes larger than 8x8, i.e., 16x16, 32x32, and 64x64, only 64 coefficients can be signaled. That is, an 8x8 base matrix can be signaled, and the remaining coefficients can be upsampled from the base matrix.

[0203] Table 9 below is an example showing the default values of ScalingList[1][matrixId][i] (i=0..3).

[0204] [Table 9]

[0205] i 0 1 2 3 ScalingList[1][1, 2, 4, 5][i] 16 16 16 16

[0206] Table 10 below is an example showing the default values of ScalingList[2][matrixId][i] (i=0..15).

[0207] [Table 10]

[0208] i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ScalingList[2][0..5][i] 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16

[0209] Table 11 below is an example showing the default values of ScalingList[3..5][matrixId][i] (i=0..63).

[0210] [Table 11]

[0211] i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ScalingList[3..5][0..5][i] 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 i-16 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ScalingList[3..5][0..5][i] 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 i-32 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ScalingList[3..5][0..5][i] 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 i-48 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ScalingList[3..5][0..5][i] 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16

[0212] Table 12 below is an example showing the default values of ScalingList[6][matrixId][i] (i=0..63).

[0213] [Table 12]

[0214] i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ScalingList[6][0,3][i] 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 i-16 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ScalingList[6][0,3][i] 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 i-32 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ScalingList[6][0,3][i] 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 i-48 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ScalingList[6][0,3][i] 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16

[0215] As described above, the default scaling list data may be used to derive a scaling factor (ScalingFactor).

[0216] The scaling factor of the 5-dimensional array ScalingFactor[sizeId][sizeId][matrixId][x][y] (where x, y = 0..(1<<sizeId)-1) can represent an array of scaling factors according to the variable sizeId shown in Table 5 and the variable matrixId shown in Table 6 above.

[0217] Table 13 below shows an example of deriving a scaling factor based on the above default scaling list according to the size of the quantization matrix.

[0218] [Table 13]

[0219]

[0220]

[0221]

[0222] For a quantization matrix of rectangular size, the scaling factor of ScalingFactor[sizeIdW][sizeIdH][matrixId][x][y] of the 5D array (where x = 0..(1<<sizeIdW)-1, y = 0..(1<<sizeIdH)-1, sizeIdW!= sizeIdH) can represent the scaling factor array according to the variables sizeIdW and sizeIdH shown in Table 15 below, and can be derived as shown in Table 14 below.

[0223] [Table 14]

[0224]

[0225]

[0226] For samples that meet the following conditions, the quantization matrix of square size should be zeroed.

[0227] -x > 32

[0228] -y > 32

[0229] - The decoded TU is not compiled using the default transform mode, (1<<sizeIdW) == 32 and x > 16

[0230] - The decoded TU is not compiled using the default transform mode, (1<<sizeIdH) == 32 and y > 16

[0231] Table 15 below shows examples of sizeIdW and sizeIdH according to the size of the quantization matrix.

[0232] [Table 15]

[0233] The size of the quantization matrix sizeIdW sizeIdH 1 0 0 2 1 1 4 2 2 8 3 3 16 4 4 32 5 5 64 6 6

[0234] In addition, as an example, the above-mentioned scaling list data (e.g., scaling_list_data()) can be described based on the syntax structure shown in Table 16 and the semantics shown in Table 17 below. As described above, the scaling list, scaling matrix, scaling factor, etc. can be derived based on the syntax elements included in the scaling list data (e.g., scaling_list_data()) disclosed in Tables 16 and 17. The same or similar procedures as in Tables 5 to 15 can be applied.

[0235] [Table 16]

[0236]

[0237] [Table 17]

[0238]

[0239]

[0240]

[0241]

[0242] In the following, this document proposes a method for efficiently signaling scaling list data when applying an adaptive frequency weighted quantization technique in the quantization / dequantization process.

[0243] Figure 8 The hierarchical structure of the compiled image / video is shown exemplarily.

[0244] refer to Figure 8 The encoded image / video is divided into the VCL (video coding layer) that handles the image / video decoding process and itself, the subsystem that sends and stores the encoded information, and the network abstraction layer (NAL) that exists between the VCL and the subsystem and is responsible for the network adaptation function.

[0245] VCL can generate VCL data including compressed image data (slice data), or generate parameter sets including picture parameter sets (PPS), sequence parameter sets (SPS), video parameter sets (VPS), etc., or supplementary enhancement information (SEI) messages that are additionally necessary for the image decoding process.

[0246] In NAL, a NAL unit can be generated by adding header information (NAL unit header) to a raw byte sequence payload (RBSP) generated in the VCL. In this case, RBSP refers to slice data, parameter sets, SEI messages, etc. generated in the VCL. The NAL unit header can include NAL unit type information specified according to the RBSP data included in the corresponding NAL unit.

[0247] In addition, NAL units can be divided into VCL NAL units and non-VCL NAL units according to the RBSP generated in the VCL. A VCL NAL unit may refer to a NAL unit including information about an image (slice data), and a non-VCL NAL unit may refer to a NAL unit containing information necessary for decoding an image (parameter set or SEI message).

[0248] The VCL NAL units and non-VCL NAL units can be transmitted over a network by attaching header information according to the data standard of the subsystem. For example, the NAL units can be converted into a data format of a predetermined standard such as the H.266 / VVC file format, the Real-time Transport Protocol (RTP), or the Transport Stream (TS), and transmitted over various networks.

[0249] As described above, in a NAL unit, a NAL unit type may be specified according to an RBSP data structure included in a corresponding NAL unit, and information on the NAL unit type may be stored and signaled in a NAL unit header.

[0250] For example, depending on whether the NAL unit includes information about an image (slice data), the NAL unit can be roughly classified into a VCL NAL unit type and a non-VCL NAL unit type. The VCL NAL unit type can be classified according to the attributes and type of the picture included in the VCL NAL unit, and the non-VCL NAL unit type can be classified according to the type of parameter set.

[0251] The following are examples of NAL unit types specified according to the type of parameter sets included in non-VCL NAL unit types.

[0252] -APS (Adaptation Parameter Set) NAL unit: type used for NAL units containing APS

[0253] -DPS (Decoding Parameter Set) NAL unit: type used for NAL units containing DPS

[0254] - VPS (Video Parameter Set) NAL unit: type used for NAL units containing VPS

[0255] - SPS (Sequence Parameter Set) NAL unit: type used for NAL units containing SPS

[0256] -PPS (Picture Parameter Set) NAL unit: type used for NAL units containing PPS

[0257] - PH (Picture Header) NAL unit: type used for NAL units including PH

[0258] The above-mentioned NAL unit type has syntax information for the NAL unit type, and the syntax information can be stored in the NAL unit header and transmitted with a signal. For example, the syntax information can be nal_unit_type, and the NAL unit type can be specified by the nal_unit_type value.

[0259] At the same time, as described above, a picture may include multiple slices, and a slice may include a slice header and slice data. In this case, a picture header may be further added to the multiple slices (slice header and slice data set) in a picture. The picture header (picture header syntax) may include information / parameters generally applicable to the picture. In this document, slices may be mixed with or replaced by tile groups. In addition, in this document, slice headers may be mixed with or replaced by type group headers.

[0260] A slice header (slice header syntax) may include information / parameters that are generally applicable to a slice. APS (APS syntax) or PPS (PPS syntax) may include information / parameters that are generally applicable to one or more slices or pictures. SPS (SPS syntax) may include information / parameters that are generally applicable to one or more sequences. VPS (VPS syntax) may include information / parameters that are generally applicable to multiple layers. DPS (DPS syntax) may include information / parameters that are generally applicable to the entire video. DPS may include information / parameters related to the concatenation of coded video sequences (CVS). In this document, high-level syntax (HLS) may include at least one of APS syntax, PPS syntax, SPS syntax, VPS syntax, DPS syntax, picture header syntax, and slice header syntax.

[0261] In this document, image / video information encoded in an encoding device and signaled to a decoding device in the form of a bitstream may include information included in a slice header, information included in a picture header, information included in an APS, information included in a PPS, information included in an SPS, information included in a VPS, and / or information included in a DPS, as well as picture partition-related information in a picture, intra / inter prediction information, residual information, in-loop filtering information, etc. In addition, the image / video information may further include information in a NAL unit header.

[0262] On the other hand, the VVC standard uses APS (Adaptive Parameter Set) to transmit information for the ALF (Adaptive Loop Filter) and LMCS (Chroma Scaling and Luma Mapping) processes. In addition, APS has an extensible structure, making it possible to transmit other data structures (i.e., different syntax structures). Therefore, this document proposes a method for parsing / signaling scaling list data for frequency-weighted quantization through APS.

[0263] The scaling list data is quantization scaling information for frequency-weighted quantization that can be applied in the quantization / dequantization process as described above, and may be a list associating a scaling factor with each frequency index.

[0264] As an embodiment, the following Table 18 shows an example of an adaptive parameter set (APS) structure for transmitting scaling list data.

[0265] [Table 18]

[0266]

[0267]

[0268] The semantics of the syntax elements included in the APS syntax of Table 18 can be shown in Table 19 below.

[0269] [Table 19]

[0270]

[0271] Referring to Tables 18 and 19, the adaptation_parameter_set_id syntax element can be parsed / signaled in an APS. The adaptation_parameter_set_id provides an identifier for the APS that can be referenced by other syntax elements. In other words, the APS can be identified based on the adaptation_parameter_set_id syntax element. The adaptation_parameter_set_id syntax element can be referred to as APS ID information. The APS can be shared between pictures and can be different for different tile groups within a picture.

[0272] In addition, the aps_params_type syntax element may be parsed / signaled in APS. aps_params_type may indicate the type of APS parameters transmitted from APS, as shown in Table 20 below. The aps_params_type syntax element may be referred to as APS parameter type information or APS type information.

[0273] For example, the following Table 20 is an example showing types of APS parameters that can be transmitted through APS, and each APS parameter type may be indicated corresponding to a value of aps_params_type.

[0274] [Table 20]

[0275]

[0276] Referring to Table 20, aps_params_type may be a syntax element for classifying the type of the corresponding APS. When the value of aps_params_type is 0, the corresponding APS type may be ALF_APS, the corresponding APS may carry ALF data, and the ALF data may include ALF parameters for deriving filters / filter coefficients. When the value of aps_params_type is 1, the corresponding APS type may be LMCS_APS, the corresponding APS may carry LMCS data, and the LMCS data may include LMCS parameters for deriving LMCS models / bins / mapping indices. When the value of aps_params_type is 2, the corresponding APS type may be SCALING_APS, the corresponding APS may carry SCALING list data, and the SCALING list data may include scaling list data parameters for deriving values of frequency-based quantization scaling matrices / scaling factors / scaling lists.

[0277] For example, as shown in Table 18 above, the aps_params_type syntax element may be parsed / signaled in APS, and in this case, when the aps_params_type indication value is 0 (i.e., aps_params_type indicates ALF_APS), ALF data (i.e., alf_data()) may be parsed / signaled. Alternatively, when the aps_params_type value is 1 (i.e., aps_params_type indicates LMCS_APS), LMCS data (i.e., lmcs_data()) may be parsed / signaled. Alternatively, when the aps_params_type value is 2 (i.e., aps_params_type indicates SCALING_APS), scaling list data (i.e., scaling_list_data()) may be parsed / signaled.

[0278] In addition, referring to Tables 18 and 19, the aps_extension_flag syntax element can be parsed / signaled in APS. aps_extension_flag can indicate whether an APS extension data flag (aps_extension_data_flag) syntax element is present. For example, aps_extension_flag can be used to provide an extension point for a higher version of the VVC standard. The aps_extension_flag syntax element can be referred to as an APS extension flag. For example, when the value of aps_extension_flag is 0, it can indicate that the APS extension data flag (aps_extension_data_flag) is not present in the APS RBSP syntax structure. Alternatively, when the value of aps_extension_flag is 1, it can indicate that the APS extension data flag (aps_extension_data_flag) is present in the APS RBSP syntax structure.

[0279] The aps_extension_data_flag syntax element may be parsed / signaled based on the aps_extension_flag syntax element. The aps_extension_data_flag syntax element may be referred to as an APS extension data flag. For example, when the value of aps_extension_flag is 1, aps_extension_data_flag may be parsed / signaled, and in this case, aps_extension_data_flag may have any value.

[0280] As described above, according to an embodiment of this document, valid scaling list data can be carried by allocating a data type (e.g., SCALING_APS) for indicating scaling list data and parsing / signaling a syntax element (e.g., aps_params_type) indicating the data type. That is, according to an embodiment of this document, the structure of the APS in which scaling list data is integrated can be used.

[0281] On the other hand, in the current VVC standard, the use of scaling list data (i.e., scaling_list_data()) can be indicated based on an indication of whether the scaling list data is available in the SPS (sequence parameter set). If a flag (i.e., sps_scaling_list_enabled_flag) is enabled (i.e., 1 or true as a case of indicating that scaling list data is available), another flag (i.e., sps_scaling_list_data_present_flag) can be parsed. In addition, when sps_scaling_list_data_present_flag is enabled (i.e., when it indicates that scaling list data is present in the SPS and is 1 or true), scaling list data (i.e., scaling_list_data()) can be parsed. That is, in the current VVC standard, the SPS sends scaling list data with a signal. In this case, because the SPS enables session negotiation and is usually sent out-of-band, the scaling list data does not need to be sent as information related to determining the scaling factor of the transform block, and can be used in the decoding process. If the encoder sends scaling list data in the SPS, the decoder needs to reserve a large amount of memory to store the information obtained from the scaling list data, and also needs to retain this information until it is used for transform block decoding. Therefore, this process may not be necessary at the SPS level, and it may be more efficient to parse / signal at a lower level. Therefore, this document proposes a hierarchical structure to efficiently parse / signal scaling list data.

[0282] In one embodiment, the scaling list data is not parsed / signaled from the higher level syntax SPS, but is parsed / signaled from the lower level syntax PPS, tile group header, slice header and / or other appropriate headers.

[0283] For example, the SPS syntax may be modified as shown in the following Table 21. The following Table 21 shows an example of an SPS syntax for describing a zoom list for a CVS.

[0284] [Table 21]

[0285]

[0286] The semantics of the syntax elements included in the SPS syntax of Table 21 can be shown in the following Table 22.

[0287] [Table 22]

[0288]

[0289] Referring to Tables 21 and 22, the scaling_list_enabled_flag syntax element may be parsed / signaled in the SPS. The scaling_list_enabled_flag syntax element may indicate whether the scaling list is available based on whether its value is 0 or 1. For example, when the scaling_list_enabled_flag value is 1, it indicates that the scaling list is used in the scaling process of the transform coefficients, and when the scaling_list_enabled_flag value is 0, it may indicate that the scaling list is not used in the scaling process of the transform coefficients.

[0290] That is, the scaling_list_enabled_flag syntax element may be referred to as a scaling list available flag and may be signaled at the SPS (or SPS level). In other words, based on the value of the scaling_list_enabled_flag signaled at the SPS level, it may be determined that the scaling list is substantially available for pictures in the CVS that reference the corresponding SPS. Furthermore, the scaling list may be obtained by signaling an additional available flag at a level lower than the SPS (e.g., a PPS, a tile group header, a slice header, and / or other appropriate headers).

[0291] As described above, according to an embodiment of this document, the scaling list (scaling_list_data()) is not directly signaled at the SPS level, and only the scaling list available flag (scaling_list_enabled_flag) can be configured to be explicitly signaled. Thereafter, the scaling list (scaling_list_data()) can be parsed separately in a lower-level syntax based on the available flag (scaling_list_enabled_flag) in the SPS. Therefore, according to an embodiment of this document, since the scaling list data can be parsed / signaled according to the hierarchical structure, coding efficiency can be further improved.

[0292] On the other hand, the presence or absence of scaling list data and the use of scaling list data are conditional on the presence of a tool enable flag. Here, the tool enable flag may be information indicating whether the corresponding tool is enabled, and may include, for example, a scaling_list_enabled_flag syntax element. That is, the scaling_list_enabled_flag syntax element may be used to indicate whether the scaling list is enabled by indicating whether scaling list data is available. However, this tool should have syntax restrictions on the decoder. That is, a constraint flag must be present to inform the decoder that this tool is not currently used to decode a coded video sequence (CVS). Therefore, this document proposes a method in which a constraint flag for scaling list data is applied.

[0293] As an embodiment, Table 23 below shows an example of a syntax (eg, general constraint information syntax) for signaling scaling list data using a constraint flag.

[0294] [Table 23]

[0295]

[0296] The semantics of the syntax elements included in the syntax of Table 23 can be shown in Table 24 below.

[0297] [Table 24]

[0298]

[0299] Referring to Tables 23 and 24, the constraint flag can be parsed / signaled through general_constraint_info(). general_constraint_info() can be referred to as information about the general constraint information field or constraint flag. For example, the no_scaling_list_constraint_flag syntax element can be used as a constraint flag. Here, the constraint flag can be used to specify a conforming bitstream attribute. For example, when the value of the no_scaling_list_constraint_flag syntax element is 1, scaling_list_enabled_flag indicates a bitstream conformance requirement that must be specified as 0, and when the value of the no_scaling_list_constraint_flag syntax element is 0, it can indicate that there is no restriction.

[0300] At the same time, as described above, according to embodiments of this document, scaling list data can be delivered using a hierarchical structure. Therefore, this document proposes a structure for scaling list data that can be parsed / signaled via a slice header. Here, the slice header can be referred to as a tile group header, or can be mixed with or replaced by a picture header.

[0301] As an embodiment, Table 25 below shows an example of a slice header syntax for signaling scaling list data.

[0302] [Table 25]

[0303]

[0304] The semantics of the syntax elements included in the slice header syntax of Table 25 can be expressed as shown in the following Table 26.

[0305] [Table 26]

[0306]

[0307]

[0308] Referring to Tables 25 and 26, the slice_pic_parameter_set_id syntax element may be parsed / signaled in the slice header. The slice_pic_parameter_set_id syntax element may indicate the identifier of the PPS being used. That is, the slice_pic_parameter_set_id syntax element is information for identifying the PPS referenced in the corresponding slice and may indicate the value of pps_pic_parameter_set_id. The value of slice_pic_parameter_set_id must be within the range of 0 to 63. The slice_pic_parameter_set_id syntax element may be referred to as PPS identification information or PPS ID information referenced by the slice.

[0309] In addition, the slice_scaling_list_enabled_flag syntax element can be parsed / signaled in the slice header. The slice_scaling_list_enabled_flag syntax element can indicate whether the scaling list is available in the current slice. For example, when the value of slice_scaling_list_enabled_flag is 1, it can indicate that the scaling list is available in the current slice, and when the value of slice_scaling_list_enabled_flag is 0, it can indicate that the scaling list is not available in the current slice. Alternatively, if slice_scaling_list_enabled_flag is not present in the slice header, its value can be inferred to be 0.

[0310] In this case, whether to parse the slice_scaling_list_enabled_flag syntax element may be determined based on the scaling_list_enabled_flag syntax element signaled in the higher-level syntax (i.e., SPS). For example, when the value of scaling_list_enabled_flag signaled from the SPS is 1 (i.e., when it is determined that scaling list data is available at a higher level), the slice_scaling_list_enabled_flag is parsed from the slice header, and it is determined whether to perform the scaling process using the scaling list in the corresponding slice.

[0311] In addition, the slice_scaling_list_aps_id syntax element can be parsed / signaled in the slice header. The slice_scaling_list_aps_id syntax element can indicate the identifier of the APS referenced in the corresponding slice. That is, the slice_scaling_list_aps_id syntax element can indicate the ID information (adaptation_parameter_set_id) of the APS including the scaling list data referenced by the corresponding slice. On the other hand, the TemporalId (i.e., temporary ID) of the APS NAL unit having the same APS ID information (adaptation_parameter_set_id) as the slice_scaling_list_aps_id (i.e., the APS NAL unit including the scaling list data) must be less than or equal to the TemporalId (i.e., temporary ID) of the slice NAL unit to be coded.

[0312] In addition, whether to parse the slice_scaling_list_aps_id syntax element can be determined based on the slice_scaling_list_enabled_flag syntax element. For example, when the value of slice_scaling_list_aps_id is 1 (i.e., when it is determined that the scaling list is available in the slice header), slice_scaling_list_aps_id can be parsed. Thereafter, scaling list data can be obtained from the APS indicated by the parsed slice_scaling_list_aps_id.

[0313] Furthermore, when multiple scaling data APSs (including multiple APSs of scaling list data) having the same value of APS ID information (adaptation_parameter_set_id) are referenced by two or more slices in the same picture, the multiple scaling data APSs having the same value (adaptation_parameter_set_id) must include the same content.

[0314] Furthermore, when the above-mentioned syntax elements are present, the value of each of the slice header syntax elements slice_pic_parameter_set_id, slice_pic_order_cnt_lsb, and slice_temporal_mvp_enabled_flag must be the same in all slice headers of a coded picture.

[0315] As described above, according to the embodiments of the present document, a hierarchical structure can be used to efficiently signal scaling list data. That is, it is possible to determine whether scaling list data is used at each lower level by first signaling an enable flag (e.g., scaling_list_enabled_flag) indicating whether scaling list data is available at a higher level (SPS syntax), and then signaling an additional available flag (e.g., slice_scaling_list_enabled_flag) at a lower level (e.g., slice header, picture header, etc.). In addition, APS ID information (e.g., slice_scaling_list_aps_id) referenced by a corresponding slice or tile group is signaled through a lower level (e.g., slice header, picture header, etc.), and scaling list data can be derived from the APS identified by the APS ID information.

[0316] In addition, the present document may apply methods such as those proposed in Tables 25 and 26 above in signaling scaling list data according to a hierarchical structure, and the scaling list data may be delivered through the structure of the slice header as shown in Table 27 below.

[0317] As an embodiment, the following Table 27 shows an example of a slice header syntax for signaling scaling list data. Here, the slice header may be referred to as a tile group header, or may be mixed with a picture header or replaced with a picture header.

[0318] [Table 27]

[0319]

[0320]

[0321] The semantics of the syntax elements included in the slice header syntax of Table 27 can be shown in the following Table 28.

[0322] [Table 28]

[0323]

[0324] Referring to Tables 27 and 28 above, the slice_pic_parameter_set_id syntax element may be parsed / signaled in the slice header. The slice_pic_parameter_set_id syntax element may indicate an identifier of the PPS being used. That is, the slice_pic_parameter_set_id syntax element is information for identifying the PPS referenced in the corresponding slice and may indicate the value of pps_pic_parameter_set_id. The value of slice_pic_parameter_set_id must be within the range of 0 to 63. The slice_pic_parameter_set_id syntax element may be referred to as PPS identification information or PPS ID information referenced by the slice.

[0325] In addition, the slice_scaling_list_aps_id syntax element can be parsed / signaled in the slice header. The slice_scaling_list_aps_id syntax element can indicate the identifier of the APS referenced in the corresponding slice. That is, the slice_scaling_list_aps_id syntax element can indicate the ID information (adaptation_parameter_set_id) of the APS including the scaling list data referenced by the corresponding slice. For example, the TemporalId (i.e., temporary ID) of the APS NAL unit having the same APS ID information (adaptation_parameter_set_id) as the slice_scaling_list_aps_id (i.e., the APS NAL unit including the scaling list data) must be less than or equal to the TemporalId (i.e., temporary ID) of the slice NAL unit to be coded.

[0326] In this case, whether to parse the slice_scaling_list_aps_id syntax element can be determined based on the scaling_list_enabled_flag syntax element signaled in the higher-level syntax (i.e., SPS). For example, when the value of scaling_list_enabled_flag signaled by the SPS is 1 (i.e., when it is determined that scaling list data is available at a higher level), slice_scaling_list_aps_id can be parsed from the slice header. Thereafter, scaling list data can be obtained from the APS indicated by the parsed slice_scaling_list_aps_id.

[0327] That is, according to the present embodiment, since the APS ID including scaling list data can be parsed when the corresponding flag (e.g., scaling_list_enabled_flag) in the SPS is enabled, as shown in Table 25 above, based on the scaling_list_enabled_flag syntax element signaled in the higher-level syntax (i.e., SPS), the APS ID (e.g., slice_scaling_list_aps_id) information including scaling list data to be referenced in a lower level (e.g., a slice header or a picture header) can be parsed.

[0328] In addition, the document proposes a method for signaling scaling list data using multiple APSs. Hereinafter, a method for efficiently signaling multiple APS IDs including scaling list data according to an embodiment of the present document will be described. This method is useful during bitstream merging.

[0329] As an embodiment, the following Table 29 shows an example of a slice header syntax for signaling scaling list data using multiple APSs. Here, the slice header may be referred to as a tile group header, or may be mixed with or replaced with a picture header.

[0330] [Table 29]

[0331]

[0332] The semantics of the syntax elements included in the slice header syntax of Table 29 can be expressed as shown in the following Table 30.

[0333] [Table 30]

[0334]

[0335]

[0336] Referring to Tables 29 and 30 above, the slice_pic_parameter_set_id syntax element may be parsed / signaled in the slice header. The slice_pic_parameter_set_id syntax element may indicate an identifier of the PPS used in the slice_pic_parameter_set_id syntax element. That is, the slice_pic_parameter_set_id syntax element is information for identifying the PPS referenced in the corresponding slice and may indicate the value of pps_pic_parameter_set_id. The value of slice_pic_parameter_set_id must be within the range of 0 to 63. The slice_pic_parameter_set_id syntax element may be referred to as PPS identification information or PPS ID information referenced by the slice.

[0337] In addition, the slice_scaling_list_enabled_flag syntax element can be parsed / signaled in the slice header. The slice_scaling_list_enabled_flag syntax element can indicate whether the scaling list is available in the current slice. For example, when the value of slice_scaling_list_enabled_flag is 1, it can indicate that the scaling list is available in the current slice, and when the value of slice_scaling_list_enabled_flag is 0, it can indicate that the scaling list is not available in the current slice. Alternatively, when the slice_scaling_list_enabled_flag is not present in the slice header, its value can be inferred to be 0.

[0338] In this case, whether to parse the slice_scaling_list_enabled_flag syntax element may be determined based on the scaling_list_enabled_flag syntax element signaled in a higher-level syntax (i.e., SPS). For example, when the value of scaling_list_enabled_flag signaled from the SPS is 1 (i.e., when it is determined that scaling list data is available at a higher layer), the slice_scaling_list_enabled_flag is parsed from the slice header, and it may be determined whether to perform the scaling process using the scaling list in the corresponding slice.

[0339] In addition, the num_scaling_list_aps_ids_minus1 syntax element may be parsed / signaled in the slice header. The num_scaling_list_aps_ids_minus1 syntax element may be information used to indicate the number of APSs including scaling list data referenced by the corresponding slice. For example, the value obtained by adding 1 to the value of the num_scaling_list_aps_ids_minus1 syntax element may be the number of APSs. The value of num_scaling_list_aps_ids_minus1 must be in the range of 0 to 7.

[0340] Here, whether to parse the num_scaling_list_aps_ids_minus1 syntax element may be determined based on the slice_scaling_list_enabled_flag syntax element. For example, when the value of slice_scaling_list_enabled_flag is 1 (i.e., when it is determined that scaling list data is available in the corresponding slice), num_scaling_list_aps_ids_minus1 may be parsed. In this case, the slice_scaling_list_aps_id[i] syntax element may be parsed / signaled based on the value of num_scaling_list_aps_ids_minus1.

[0341] That is, slice_scaling_list_aps_id[i] may indicate the identifier (adaptation_parameter_set_id) of the APS including the i-th scaling list data (i.e., the i-th scaling data APS). In other words, APS ID information may be signaled as many as the number of APSs indicated by the num_scaling_list_aps_ids_minus1 syntax element. On the other hand, the TemporalId (i.e., temporary ID) of the APS NAL unit having the same APS ID information (adaptation_parameter_set_id) as slice_scaling_list_aps_id[i] (i.e., the APS NAL unit including the scaling list data) must be less than or equal to the TemporalId (i.e., temporary ID) of the slice NAL unit to be coded.

[0342] Furthermore, when multiple scaling data APSs (including multiple APSs of scaling list data) having the same value of APS ID information (adaptation_parameter_set_id) are referenced by two or more slices in the same picture, the multiple scaling data APSs having the same value (adaptation_parameter_set_id) must include the same content.

[0343] The following figures are created to illustrate specific examples of this document. The names of specific devices or specific terms or names (e.g., names of syntax / syntax elements, etc.) described in the figures are provided only as examples, so that the technical features of this document are not limited to the specific names used in the following figures.

[0344] Figure 9 and Figure 10 An example of a video / image encoding method and related components according to an embodiment of this document is schematically shown.

[0345] Figure 9 The method disclosed in Figure 2 Specifically, Figure 9 Step S900 can be performed by Figure 2 The subtractor 231 shown in FIG performs, Figure 9 Step S910 can be performed by Figure 2 The converter 232 shown in FIG. Figure 9 Step S920 can be performed by Figure 2 The illustrated quantizer 233 performs, and Figure 9 Steps S930 to S940 can be performed by Figure 2The entropy encoder 240 shown in FIG is executed. In addition, it is possible to perform Figure 9 The method disclosed in, including the above embodiments in this document. Figure 9 In the embodiment, detailed descriptions of contents overlapping with the above embodiments will be omitted or simplified.

[0346] refer to Figure 9 , the encoding apparatus may derive residual samples for the current block ( S900 ).

[0347] As an embodiment, the encoding device may first determine the prediction mode for the current block and derive prediction samples. For example, the encoding device may determine whether to perform inter-frame prediction or intra-frame prediction on the current block, or may determine a specific inter-frame prediction mode or a specific intra-frame prediction mode based on the RD cost. The encoding device may derive prediction samples for the current block by performing prediction according to the determined prediction mode. In this case, various prediction methods disclosed in this document, such as inter-frame prediction or intra-frame prediction, may be applied. In addition, the encoding device may generate and encode information related to the prediction applied to the current block (e.g., prediction mode information). In addition, the encoding device may derive residual samples by comparing the prediction samples for the current block with the original samples.

[0348] The encoding apparatus may derive transform coefficients based on the residual samples ( S910 ).

[0349] As an embodiment, the encoding device may derive transform coefficients by performing a transform process on the residual samples. In this case, the encoding device may determine whether to apply the transform to the current block in consideration of coding efficiency. That is, the encoding device may determine whether to apply the transform to the residual samples. For example, when the transform is not applied to the residual samples, the encoding device may derive the residual samples as transform coefficients. Alternatively, when the transform is applied to the residual samples, the encoding device may derive the transform coefficients by performing the transform on the residual samples. In this case, the encoding device may generate and encode transform skip flag information based on whether the transform is applied to the current block. The transform skip flag information may be information indicating whether the transform is applied or skipped with respect to the current block.

[0350] The encoding apparatus may derive a quantized transform coefficient based on the transform coefficient ( S920 ).

[0351] In one embodiment, the encoding device can derive the quantized transform coefficients by performing a quantization process on the transform coefficients. In this case, the encoding device can apply frequency-weighted quantization that adjusts the quantization strength according to the frequency. In this case, the quantization process can be further performed based on the quantization scale value for each frequency. The quantization scaling value for frequency-weighted quantization can be derived using a scaling matrix. For example, the encoding device / decoding device can use a predefined scaling matrix, and the encoding device can configure and encode frequency quantization scaling information about the scaling matrix, and can send it to the decoding device with a signal. The frequency quantization scaling information may include scaling list data. The (modified) scaling matrix can be derived based on the scaling list data.

[0352] Furthermore, the encoding device may perform a dequantization process in the same manner as the decoding device. In this case, the encoding device may derive a (modified) scaling matrix based on the scaling list data, and may derive reconstructed transform coefficients by applying dequantization to the quantized transform coefficients based thereon. In this case, the reconstructed transform coefficients may differ from the original transform coefficients due to losses in the transform / quantization process.

[0353] Here, the scaling matrix may refer to the above-mentioned frequency-based quantization scaling matrix, and for the sake of convenience of description may be used interchangeably or replaced with quantization scaling matrix, quantization matrix, scaling matrix, scaling list, etc., and is not limited to the specific names used in this document.

[0354] That is, the encoding device may further apply frequency-weighted quantization when performing the quantization process. In this case, scaling list data may be generated as information about the scaling matrix. Since this process has been described in detail using Tables 5 to 17 as an example, redundant content or detailed description will be omitted in this embodiment.

[0355] The encoding apparatus may generate residual information including information about the quantized transform coefficient and an APS (Adaptive Parameter Set) ( S930 ).

[0356] Here, the residual information is information generated by the transformation and / or quantization process, and may be information about the quantized transformation coefficient, for example, information about the value of the quantized transformation coefficient, position information, transformation technology, transformation kernel, quantization parameter, etc.

[0357] In addition, when frequency-weighted quantization is further applied when deriving quantized transform coefficients in the quantization process, scaling list data can be generated. In this case, the encoding device can generate information related to the scaling list data, for example, an APS including the scaling list data.

[0358] As an embodiment, the APS may include APS ID information and APS type information. The APS ID information may indicate an APS identifier, and the APS type information may indicate that the APS is an APS associated with the zoom list data. The APS may include zoom list data based on the APS type information.

[0359] The encoding device may encode the image information (or video information) (S940). Here, the image information may include residual information. In addition, the image information may include APS. In addition, the image information may include information related to prediction (e.g., prediction mode information). In addition, the image information may include information related to scaling list data. That is, the image information may include various information derived from the encoding process and may be encoded by including such various information.

[0360] As an example, the image information may include various information according to the above-described embodiments in this document, and may include information disclosed in at least one of Tables 1 to 30 above.

[0361] For example, image information may include an adaptive parameter set (APS). The APS may include APS ID information (APS identification information) and APS type information (APS parameter type information). In addition, the APS may include scaling list data based on the APS type information. The scaling list data may include scaling list parameters for deriving a scaling list / scaling matrix / scaling factor used in the quantization / dequantization process described above. In other words, the scaling list data may include syntax elements for constructing a scaling list.

[0362] As an example, the APS may be configured as shown in Table 18 above. The APS ID information (APS identification information) may be the adaptation_parameter_set_id described in Tables 18 and 19 above. The APS type information may be the aps_params_type described in Tables 18 to 20 above. For example, when the type information (e.g., aps_params_type) of the APS parameter is the SCALING_APS type associated with an indication that it is an APS including scaling list data (or when the value of the type information (e.g., aps_params_type) of the APS parameter is equal to 2), the APS may include scaling list data (e.g., scaling_list_data()). That is, the encoding device may signal the scaling list data (e.g., scaling_list_data()) through the APS based on the SCALING_APS type information indicating that it is an APS including scaling list data.

[0363] In addition, for example, the image information may include header information. The header information may be header information related to a picture or a slice including the current block, and may include, for example, a picture header or a slice header. The header information may include APS ID information related to scaling list data referenced by the slice or picture related to the header information. The APS ID information related to scaling list data included in the header information may indicate ID information of the APS including the scaling list data. For example, the APS ID information related to scaling list data included in the header information may be slice_scaling_list_aps_id described in Tables 25 to 28 above, and may be identification information of the APS (including scaling list data) referenced by the slice / picture including the current block. That is, the APS including the scaling list data can be identified based on the APS ID information related to the scaling list data.

[0364] Furthermore, for example, the image information may include header information, such as a slice header or picture header associated with a slice or picture including the current block. The header information may include APS ID number information indicating the number of APS ID information associated with the scaling list data. In this case, the header information may include APS ID information associated with a plurality of scaling list data based on the APS ID number information. In other words, the header information may include APS ID information associated with scaling list data corresponding to the number of APS IDs derived based on the information regarding the number of APS IDs.

[0365] As an example, the APS ID number information may be num_scaling_list_aps_ids_minus1 described in Tables 29 and 30 above. As described in Table 29, a value obtained by adding 1 to the value of num_scaling_list_aps_ids_minus1 may be the number of APS IDs. Therefore, as many slice_scaling_list_aps_ids as the number of APS IDs (the value of num_scaling_list_aps_ids_minus1 plus 1) may be included in the header information.

[0366] In addition, for example, the image information may include a sequence parameter set (SPS). The SPS may include first available flag information related to indicating whether scaling list data is available. For example, the SPS may be configured as shown in Table 21, and the first available flag information may be scaling_list_enabled_flag described in Tables 21 and 22 above.

[0367] At this time, based on the first available flag information (e.g., scaling_list_enabled_flag) related to indicating that the scaling list data is available (e.g., when the value of the first available flag information (e.g., scaling_list_enabled_flag) is equal to 1 or true), the header information may include APS ID information (e.g., slice_scaling_list_aps_id) related to the scaling list data. As an example, the encoding device may signal the ID information (e.g., slice_scaling_list_aps_id) of the APS including the scaling list data through the header information based on the first available flag information (e.g., scaling_list_enabled_flag) as shown in Tables 25 and 27 above.

[0368] In addition, for example, the header information may include second available flag information related to indicating whether the scaling list data is available in the picture or slice. As an example, the second available flag information may be slice_scaling_list_enabled_flag described in Tables 25 and 26 above.

[0369] At this time, based on first usability flag information (e.g., scaling_list_enabled_flag) related to indicating that the scaling list data is usable (e.g., when the value of the first usability flag information (e.g., scaling_list_enabled_flag) is equal to 1 or true), the header information may include second usability flag information (e.g., slice_scaling_list_enabled_flag). Furthermore, based on the second usability flag information (e.g., slice_scaling_list_enabled_flag) (e.g., when the value of the second usability flag information (e.g., slice_scaling_list_enabled_flag) is equal to 1 or true), the header information may include APS ID information (e.g., slice_scaling_list_aps_id) related to the scaling list data. As an example, the encoding device may signal second available flag information (e.g., slice_scaling_list_enabled_flag) through header information based on the first available flag information (e.g., scaling_list_enabled_flag) signaled from the SPS as shown in Table 25 above, and may then signal APS ID information (e.g., slice_scaling_list_aps_id) related to the scaling list data through header information based on the second available flag information (e.g., slice_scaling_list_enabled_flag).

[0370] In addition, for example, the image information may include constraint flag information regarding the use of the first available flag information. For example, the constraint flag information may be the no_scaling_list_constraint_flag described in Tables 23 and 24 above. The constraint flag information (e.g., no_scaling_list_constraint_flag) may be signaled by being included in a general constraint information syntax (e.g., general_constraint_info()). For example, when the value of the constraint flag information (e.g., no_scaling_list_constraint_flag) is equal to 1, the general constraint information syntax (e.g., general_constraint_info()) is restricted so that the value of the first available flag information (e.g., scaling_list_enabled_flag) is set to 0. Alternatively, when the value of the constraint flag information (e.g., no_scaling_list_constraint_flag) is equal to 0, it may be indicated that there is no constraint on the first available flag information (e.g., scaling_list_enabled_flag).

[0371] The image information including the various information described above can be encoded and output in the form of a bitstream. The bitstream can be sent to a decoding device via a network or a (digital) storage medium. Here, the network can include a broadcast network and / or a communication network, and the digital storage medium can include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD.

[0372] Figure 11 and Figure 12 An example of a video / image decoding method and related components according to an embodiment of this document is schematically shown.

[0373] Figure 11 The method disclosed in Figure 3 The illustrated decoding apparatus 300 performs. Specifically, Figure 11 Steps S1100 to S1110 can be performed by Figure 3 The entropy decoder 310 shown in FIG is executed, and Figure 11 Steps S1120 to S1130 can be performed by Figure 3 The dequantizer 321 shown in FIG performs, Figure 11 Step S1140 can be performed by Figure 3 The inverse transformer 322 shown in FIG is executed, and Figure 11 Step 1150 may be performed by Figure 3 The adder 340 shown in the figure performs. In addition, it is possible to perform Figure 11The method disclosed in, including the above embodiments in this document. Figure 11 In the embodiment, detailed descriptions of contents overlapping with the above embodiments will be omitted or simplified.

[0374] refer to Figure 11 , the decoding device can obtain image information (or video information) from the bit stream (S1100).

[0375] As an embodiment, the decoding device can derive information necessary for image reconstruction (or picture reconstruction) (e.g., video / image information) by parsing the bitstream. In this case, the image information may include residual information, and the residual information may include information such as information about the value of the quantized transform coefficient, position information, transform technology, transform kernel, and quantization parameter. In addition, the image information may include APS (Adaptive Parameter Set). In addition, the image information may include information about scaling list data. In addition, the image information may include information related to prediction (e.g., prediction mode information). That is, the image information may include various information required in the decoding process, and may be decoded based on coding methods such as exponential Golomb coding, CAVLC, CABAC, etc.

[0376] As an example, the image information may include various information according to the above-described embodiments in this document, and may include information disclosed in at least one of Tables 1 to 30 above.

[0377] For example, the image information may include an adaptive parameter set (APS). The APS may include APS ID information (APS identification information) and APS type information (APS parameter type information). The APS ID information may indicate an APS identifier, and the APS type information may indicate that the APS is an APS associated with scaling list data. The APS may include scaling list data based on the APS type information. The scaling list data may include scaling list parameters for deriving a scaling list / scaling matrix / scaling factor used in the quantization / dequantization process as described above. In other words, the scaling list data may include syntax elements for constructing a scaling list.

[0378] As an example, the APS may be configured as shown in Table 18 above. The APS ID information (APS identification information) may be the adaptation_parameter_set_id described in Tables 18 and 19 above. The APS type information may be the aps_params_type described in Tables 18 to 20 above. For example, when the type information (e.g., aps_params_type) of the APS parameter is the SCALING_APS type associated with an indication that it is an APS including scaling list data (or when the value of the type information (e.g., aps_params_type) of the APS parameter is equal to 2), the APS may include scaling list data (e.g., scaling_list_data()). That is, the decoding device may obtain and parse the scaling list data (e.g., scaling_list_data()) through the APS based on the SCALING_APS type information indicating that it is an APS including scaling list data.

[0379] In addition, for example, the image information may include header information. The header information may be header information related to a picture or a slice including the current block, and may include, for example, a picture header or a slice header. The header information may include APS ID information related to scaling list data referenced by the slice or picture related to the header information. The APS ID information related to scaling list data included in the header information may indicate ID information of the APS including the scaling list data. For example, the APS ID information related to scaling list data included in the header information may be slice_scaling_list_aps_id described in Tables 25 to 28 above, and may be identification information of the APS (including scaling list data) referenced by the slice / picture including the current block. That is, the decoding device may obtain the header information included in the image information from the bitstream, and may identify the APS including the scaling list data based on the APS ID information related to the scaling list data in the header information. And the decoding device may obtain the scaling list data from the identified APS.

[0380] Furthermore, for example, the image information may include header information, such as a slice header or picture header associated with a slice or picture including the current block. The header information may include APS ID number information indicating the number of APS ID information associated with the scaling list data. In this case, the header information may include APS ID information associated with a plurality of scaling list data based on the APS ID number information. In other words, the header information may include APS ID information associated with scaling list data corresponding to the number of APS IDs derived based on the information regarding the number of APS IDs.

[0381] As an example, the APS ID number information may be num_scaling_list_aps_ids_minus1 described in Tables 29 and 30 above. As described in Table 29, the value obtained by adding 1 to the value of num_scaling_list_aps_ids_minus1 may be the number of APS IDs. Therefore, as many slice_scaling_list_aps_ids as the number of APS IDs (the value of num_scaling_list_aps_ids_minus1 plus 1) may be included in the header information.

[0382] In addition, for example, the image information may include a sequence parameter set (SPS). The SPS may include first available flag information related to indicating whether scaling list data is available. For example, the SPS may be configured as shown in Table 21, and the first available flag information may be scaling_list_enabled_flag described in Tables 21 and 22 above.

[0383] At this time, based on the first available flag information (e.g., scaling_list_enabled_flag) related to indicating that the scaling list data is available (e.g., when the value of the first available flag information (e.g., scaling_list_enabled_flag) is equal to 1 or true), the header information may include APS ID information (e.g., slice_scaling_list_aps_id) related to the scaling list data. As an example, the decoding device may obtain the ID information (e.g., slice_scaling_list_aps_id) of the APS including the scaling list data through the header information based on the first available flag information (e.g., scaling_list_enabled_flag) as shown in Tables 25 and 27 above.

[0384] In addition, for example, the header information may include second available flag information related to indicating whether the scaling list data is available in the picture or slice. As an example, the second available flag information may be slice_scaling_list_enabled_flag described in Tables 25 and 26 above.

[0385] At this time, based on first usability flag information (e.g., scaling_list_enabled_flag) related to indicating that the scaling list data is usable (e.g., when the value of the first usability flag information (e.g., scaling_list_enabled_flag) is equal to 1 or true), the header information may include second usability flag information (e.g., slice_scaling_list_enabled_flag). Furthermore, based on the second usability flag information (e.g., slice_scaling_list_enabled_flag) (e.g., when the value of the second usability flag information (e.g., slice_scaling_list_enabled_flag) is equal to 1 or true), the header information may include APS ID information (e.g., slice_scaling_list_aps_id) related to the scaling list data. For example, the decoding device can obtain second available flag information (e.g., slice_scaling_list_enabled_flag) through header information based on the first available flag information (e.g., scaling_list_enabled_flag) sent by the SPS signal as shown in Table 25 above, and can then obtain APS ID information related to the scaling list data (e.g., slice_scaling_list_aps_id) through header information based on the second available flag information (e.g., slice_scaling_list_enabled_flag).

[0386] In addition, for example, the image information may include constraint flag information regarding the use of the first available flag information. For example, the constraint flag information may be the no_scaling_list_constraint_flag described in Tables 23 and 24 above. The constraint flag information (e.g., no_scaling_list_constraint_flag) may be signaled by being included in a general constraint information syntax (e.g., general_constraint_info()). For example, when the value of the constraint flag information (e.g., no_scaling_list_constraint_flag) is equal to 1, the general constraint information syntax (e.g., general_constraint_info()) is restricted so that the value of the first available flag information (e.g., scaling_list_enabled_flag) is set to 0. Alternatively, when the value of the constraint flag information (e.g., no_scaling_list_constraint_flag) is equal to 0, it may be indicated that there is no constraint on the first available flag information (e.g., scaling_list_enabled_flag).

[0387] The decoding apparatus may derive a quantized transform coefficient for the current block based on the residual information ( S1110 ).

[0388] As an embodiment, the decoding device may obtain residual information included in the image information. The residual information may include information such as information about the value of the quantized transform coefficient, position information, transform technology, transform kernel, and quantization parameter as described above. The decoding device may derive the quantized transform coefficient for the current block based on the quantized transform coefficient information included in the residual information.

[0389] The decoding apparatus may derive scaling list data based on the APS ( S1120 ).

[0390] As an embodiment, the decoding device may obtain the APS included in the image information and may obtain the scaling list data based on the APS type information included in the APS. For example, the decoding device may obtain the scaling list data included in the APS based on the SCALING_APS type information associated with the APS indicating that it is an APS including the scaling list data.

[0391] At this time, in deriving the scaling list data, the decoding device can determine whether to apply frequency-weighted quantization in the dequantization process (that is, whether to use the (frequency-based quantization) scaling list to derive the transform coefficients in the dequantization process). For example, the decoding device determines whether to use the scaling list data based on a first available flag obtained from the SPS included in the image information and / or second available flag information obtained from the header information included in the image information. If it is determined to use the scaling list data based on the first available flag and / or the second available flag information, the decoding device can obtain APS ID information related to the scaling list data included in the header information, and can derive the scaling list data from the APS identified by the APS identification information related to the scaling list data.

[0392] The decoding apparatus may derive a transform coefficient by performing a dequantization process on the quantized transform coefficient based on the scaling list data ( S1130 ).

[0393] As an embodiment, the decoding device may derive the transform coefficients by performing a dequantization process on the quantized transform coefficients. In this case, the decoding device may apply frequency-weighted quantization that adjusts the quantization strength according to the frequency. In this case, the dequantization process may be further performed based on the quantization scaling value of each frequency. The quantization scaling value for frequency-weighted quantization may be derived using a scaling matrix. For example, the decoding device may use a predefined scaling matrix, or may use frequency quantization scaling information about the scaling matrix signaled from the encoding device. The frequency quantization scaling information may include scaling list data. The (modified) scaling matrix may be derived based on the scaling list data.

[0394] That is, the decoding device may further apply frequency-weighted quantization during the dequantization process. In this case, the decoding device may derive transform coefficients by applying a dequantization process to the quantized transform coefficients based on the scaling list data. In this case, the decoding device may derive a scaling matrix based on the scaling list data, may derive a scaling factor based on the scaling matrix, and may derive transform coefficients by performing dequantization based on the scaling factor. Since the process of performing scaling based on the scaling list data has been described in detail with reference to Tables 5 to 17, redundant content or detailed description will be omitted in this embodiment.

[0395] The decoding apparatus may derive residual samples based on the transform coefficients ( S1140 ).

[0396] As an embodiment, the decoding device may derive residual samples of the current block by performing an inverse transform process on the transform coefficients of the current block. In this case, the decoding device may obtain information indicating whether the inverse transform is applied to the current block (i.e., transform skip flag information), and derive residual samples based on this information (i.e., transform skip flag information).

[0397] For example, when inverse transform is not applied to the transform coefficient (when the value of the transform skip flag information for the current block is equal to 1), the decoding device may derive the transform coefficient as the residual sample of the current block. Alternatively, when inverse transform is applied to the transform coefficient (when the value of the transform skip flag information for the current block is equal to 0), the decoding device may perform inverse transform on the transform coefficient to derive the residual sample of the current block.

[0398] The decoding apparatus may generate reconstructed samples based on the residual samples ( S1150 ).

[0399] As an embodiment, the decoding device may determine whether to perform inter-frame prediction or intra-frame prediction on the current block based on the prediction information (e.g., prediction mode information) included in the image information, and derive the prediction sample of the current block by performing prediction according to the determination. Furthermore, the decoding device may generate a reconstructed sample based on the prediction sample and the residual sample. At this time, the decoding device may directly use the prediction sample as the reconstructed sample according to the prediction mode, or may generate the reconstructed sample by adding the residual sample to the prediction sample. In addition, a reconstructed block or a reconstructed picture may be derived based on the reconstructed sample. Thereafter, as described above, if necessary, the decoding device may apply an in-loop filtering process such as a deblocking filter and / or an SAO process to the reconstructed picture in order to improve the subjective / objective picture quality.

[0400] In the above-mentioned embodiments, although these methods have been described based on flowcharts in the form of a series of steps or units, the embodiments of this document are not limited to the order of these steps, and some of these steps may be performed in an order different from that of other steps or may be performed simultaneously with other steps. In addition, it will be understood by those skilled in the art that the steps shown in the flowcharts are not exclusive, and without affecting the scope of rights of this document, these steps may include additional steps or one or more steps in the flowcharts may be deleted.

[0401] The above-mentioned method according to this document may be implemented in software form, and the encoding device and / or decoding device according to this document may be included in an apparatus for performing image processing, such as a TV, computer, smart phone, set-top box, or display device.

[0402] In this document, when the embodiments are implemented in software form, the above-mentioned methods can be implemented as modules (programs, functions, etc.) for performing the above-mentioned functions. The modules can be stored in a memory and executed by a processor. The memory can be arranged inside or outside the processor and connected to the processor by various well-known means. The processor may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits and / or data processing devices. The memory may include a read-only memory (ROM), a random access memory (RAM), a flash memory, a memory card, a storage medium and / or other storage devices. That is, the embodiments described in this document can be implemented and executed on a processor, a microprocessor, a controller or a chip. For example, the functional units illustrated in the accompanying drawings can be implemented and executed on a computer, a processor, a microprocessor, a controller or a chip. In this case, the information (e.g., information about instructions) or the algorithm used for such implementation can be stored in a digital storage medium.

[0403] In addition, the decoding device and encoding device to which this document is applied may be included in multimedia broadcast transmission and reception devices, mobile communication terminals, home theater video devices, digital theater video devices, surveillance cameras, video chat devices, real-time communication devices such as video communication, mobile streaming devices, storage media, cameras, video on demand (VoD) service providing devices, over-the-top (OTT) video devices, Internet streaming service providing devices, three-dimensional (3D) video devices, virtual reality (VR) devices, augmented reality (AR) devices, video phone video devices, transportation terminals (e.g., vehicle (including autonomous vehicle) terminals, aircraft terminals, and ship terminals), and medical video devices, and may be used to process video signals or data signals. For example, over-the-top (OTT) video devices may include game consoles, Blueray players, Internet access TVs, home theater systems, smartphones, tablet PCs, and digital video recorders (DVRs).

[0404] In addition, the processing method of the present document can be generated in the form of a program executed by a computer and can be stored in a computer-readable recording medium. The multimedia data with a data structure according to the present document can also be stored in a computer-readable recording medium. Computer-readable recording media include all kinds of storage devices storing computer-readable data. Computer-readable recording media may include, for example, Blueray discs (BD), universal serial buses (USB), ROMs, PROMs, EPROMs, EEPROMs, RAMs, CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices. In addition, computer-readable recording media include media implemented in the form of carrier waves (for example, transmitted over the Internet). In addition, the bit stream generated using the encoding method can be stored in a computer-readable recording medium or can be transmitted through wired and wireless communication networks.

[0405] In addition, the embodiments of this document may be implemented as a computer program product using program code. The program code may be executed by a computer according to the embodiments of this document. The program code may be stored on a carrier wave that can be read by a computer.

[0406] Figure 13 An example of a content streaming system to which the embodiments disclosed in this document can be applied is illustrated.

[0407] refer to Figure 13 The content streaming media system to which the embodiment of the present invention is applied may basically include an encoding server, a streaming server, a web server, a media storage, a user device, and a multimedia input device.

[0408] The encoding server compresses content input from a multimedia input device such as a smartphone, a camera, or a camcorder into digital data to generate a bitstream, and transmits the bitstream to the streaming server. As another example, when a multimedia input device such as a smartphone, a camera, or a camcorder directly generates a bitstream, the encoding server may be omitted.

[0409] A bitstream may be generated by applying the encoding method or the bitstream generation method of the embodiments of this document, and the streaming server may temporarily store the bitstream in a process of transmitting or receiving the bitstream.

[0410] The streaming server transmits multimedia data to user devices via a web server based on user requests. The web server also serves as a medium for informing users of services. When a user requests a desired service from the web server, the web server transmits the request to the streaming server, which then transmits the multimedia data to the user. In this case, the content streaming system may include a separate control server. In this case, the control server is used to control commands and responses between devices in the content streaming system.

[0411] The streaming server can receive content from a media storage device and / or an encoding server. For example, when receiving content from an encoding server, the content can be received in real time. In this case, in order to provide a stable streaming service, the streaming server can store the bitstream for a predetermined time.

[0412] Examples of user devices may include mobile phones, smart phones, laptop computers, digital broadcast terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigators, touch-screen PCs, tablet PCs, ultrabooks, wearable devices (e.g., smart watches, smart glasses, head-mounted displays), digital TVs, desktop computers, digital signage, etc.

[0413] The individual servers in the content streaming system may operate as distributed servers, in which case data received from the individual servers may be distributed.

[0414] The claims described herein can be combined in various ways. For example, the technical features of the method claims of this specification can be combined and implemented as a device, and the technical features of the device claims of this specification can be combined and implemented as a method. Furthermore, the technical features of the method claims of this specification and the technical features of the device claims of this specification can be combined and implemented as a device, and the technical features of the method claims of this specification and the technical features of the device claims of this specification can be combined and implemented as a method.

Claims

1. A method for decoding an image, the method comprising: Obtaining image information including residual information and adaptive parameter set APS from the bit stream; deriving quantized transform coefficients for a current block based on the residual information; exporting zoom list data based on the APS; deriving transform coefficients by performing a dequantization process on the quantized transform coefficients based on the scaling list data; deriving residual samples by performing an inverse transform process based on the transform coefficients; as well as Generate a reconstructed sample based on the residual sample, The APS includes APSID information and APS type information. The APSID information indicates the identifier of the APS. The APS type information indicates that the APS is related to the zoom list data. wherein, based on the APS type information, the scaling list data is included in the APS, The image information includes a sequence parameter set SPS and a slice header of a slice. The SPS includes first available flag information indicating whether the scaling list data in the APS is available. wherein the slice header includes second available flag information related to indicating whether the scaling list data in the APS is available so as to decode the slice based on the first available flag information indicating that the scaling list data in the APS is available, and The APS is included in a first non-VCL network abstraction layer NAL unit of the image information, the SPS is included in a second non-VCL NAL unit of the image information, and the slice is included in a VCL NAL unit of the image information.

2. An image encoding method performed by an image encoding apparatus, the method comprising: derive residual samples for the current block; deriving transform coefficients by performing a transform process based on the residual samples; deriving quantized transform coefficients by performing a quantization process on the transform coefficients; generating an adaptive parameter set APS and residual information about the quantized transform coefficients; as well as encoding the image information including the residual information and the APS, The APS includes APSID information and APS type information. The APSID information indicates the identifier of the APS. The APS type information indicates that the APS is related to zoom list data. Wherein, based on the APS type information, the APS includes the zoom list data, The image information includes a sequence parameter set SPS and a slice header of a slice. The SPS includes first available flag information indicating whether the scaling list data in the APS is available. wherein the slice header includes second available flag information related to indicating whether the scaling list data in the APS is available so as to decode the slice based on the first available flag information indicating that the scaling list data in the APS is available, and The APS is included in a first non-VCL network abstraction layer NAL unit of the image information, the SPS is included in a second non-VCL NAL unit of the image information, and the slice is included in a VCL NAL unit of the image information.

3. A computer-readable digital storage medium storing a bitstream generated by a method comprising: derive residual samples for the current block; deriving transform coefficients by performing a transform process based on the residual samples; deriving quantized transform coefficients by performing a quantization process on the transform coefficients; generating an adaptive parameter set APS and residual information about the quantized transform coefficients; as well as encoding the image information including the residual information and the APS to generate the bitstream, The APS includes APSID information and APS type information. The APSID information indicates the identifier of the APS. The APS type information indicates that the APS is related to zoom list data. Wherein, based on the APS type information, the APS includes the zoom list data, The image information includes a sequence parameter set SPS and a slice header of a slice. The SPS includes first available flag information indicating whether the scaling list data in the APS is available. wherein the slice header includes second available flag information related to indicating whether the scaling list data in the APS is available so as to decode the slice based on the first available flag information indicating that the scaling list data in the APS is available, and The APS is included in a first non-VCL network abstraction layer NAL unit of the image information, the SPS is included in a second non-VCL NAL unit of the image information, and the slice is included in a VCL NAL unit of the image information.

4. A method for transmitting data of image information, the method comprising: Obtaining a bitstream of the image information including residual information and an adaptive parameter set (APS), wherein the bitstream is generated based on: deriving residual samples for a current block, deriving transform coefficients by performing a transform process based on the residual samples, deriving quantized transform coefficients by performing a quantization process on the transform coefficients, generating the APS and the residual information about the quantized transform coefficients, and encoding the image information including the residual information and the APS; transmitting the data of the bitstream including the image information including the residual information and the APS, The APS includes APSID information and APS type information. The APSID information indicates the identifier of the APS. wherein the APS type information indicates that the APS is associated with zoom list data, and Wherein, based on the APS type information, the APS includes the zoom list data, The image information includes a sequence parameter set SPS and a slice header. The SPS includes first available flag information indicating whether the scaling list data in the APS is available. wherein the slice header includes second available flag information related to indicating whether the scaling list data in the APS is available so as to decode the slice based on the first available flag information indicating that the scaling list data in the APS is available, and The APS is included in a first non-VCL network abstraction layer NAL unit of the image information, the SPS is included in a second non-VCL NAL unit of the image information, and the slice is included in a VCL NAL unit of the image information.

Images